Questions on Algebra: Radicals -- complicated equations involving roots answered by real tutors!

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Question 1095268: how much xsquare -y square ? if x+y=66 xy=9

Found 4 solutions by KMST, ikleyn, greenestamps, MathTherapy:
Answer by KMST(5345) About Me  (Show Source):
You can put this solution on YOUR website!
ONE WAY:
Maybe we know about solving quadratic equations.
Sometimes we can solve a quadratic equation such as z%5E2%2Bbz%2Bc=0 by factoring if we find two integers p q such that p%2Bq=-b and pq=c .
Then those values for p and q are the solutions of the equation and the equation is really
z%5E2-%28p%2Bq%29z%2Bpq=%28z-p%29%28z-q%29=0 .
The solutions to a quadratic equation of the form z%5E2%2Bbz%2Bc=0 are always two numbers whose sum and product can be found are -b and c respectively.
Unfortunately, sometimes those numbers are irrational, or even imaginary, and then factoring is not an option.
Then, w must use algebra to "complete the square" and then solve, or apply the dreaded quadratic formula
that says the solutions to an equation of the form ax%5E2%2Bbx%2Bc=0 are given by
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
To avoid confusion, I used z for the variable instead of x , and I prefer equations where the leading coefficient is a=1 , so I wrote my equation as z%5E2%2Bbz%2Bc=0 .
I will make b=-%28p%2Bq%29=-66 and c=pq=9 to get z%5E2-66z%2B9=0.
The solutions will be the numbers p and q (or x and y ) that add up to x%2By=66 and whose product is x%2Ay=9 .
The quadratic formula tells me that the solution are given by

The solutions to the equation are %2833%2B6sqrt%2830%29%29 and %2833-12sqrt%2830%29%29
One is x and the other is y , but there is no way to guess which was intended to be x and which was intended to be y .
x%5E2 and y%5E2 are
and

The possible answers are
and

ANOTHER APPROACH:
We know that x%5E2-y%5E2=%28x%2By%29%28x-y%29 . If we only knew the value of %28x-y%29 we could easily find the value of x%5E2-y%5E2

We know that %28x-y%29%5E2=x%5E2%2By%5E2-2xy , but to calculate %28x-y%29%5E2 we would need the value of x%5E2%2By%5E2

We know that %28x%2By%29%5E2=x%5E2%2By%5E2%2B2xy and we know the values of %28x%2By%29=66=2%2A3%2A11 and xy=9=3%5E2
Substituting the known values we get 66%5E2=x%5E2%2By%5E2%2B2%2A9 --> 66%5E2=x%5E2%2By%5E2%2B18 --> x%5E2%2By%5E2=66%5E2-18=4338
Now we can use that value of to calculate the values of %28x-y%29%5E2 and %28x-y%29 , and from that find the value of x%5E2-y%5E2

%28x-y%29%5E2=x%5E2%2By%5E2-2xy=4338-2%2A9=4338-18=4320=30%2A144=30%2A12%5E2

Then %28x-y%29=%22+%22+%2B-+sqrt%2830-12%5E2%29=%22+%22+%2B-+12sqrt%2830%29

Multiplying times

Answer by ikleyn(53748) About Me  (Show Source):
You can put this solution on YOUR website!
.
How much x square -y square ? if x+y=66 xy=9
~~~~~~~~~~~~~~~~~~~~~~~


Tutor @greenestamps provided the answer  x%5E2-y%5E2 = 792sqrt%2830%29.

This answer is correct,  but incomplete.

This problem has a symmetry  (x.y) <---> (y,x).

In other words, values x and y can be rearranged.

It means that together with the answer  x%5E2-y%5E2 = 792sqrt%2830%29
 another answer  x%5E2-y%5E2 = -792sqrt%2830%29  is valid and is possible,  too.

So, the complete answer to the problem is THIS:

        - under given conditions,  x%5E2-y%5E2  may have two different values.
           One possible value is  792sqrt%2830%29;  another possible value is  -792sqrt%2830%29.



Answer by greenestamps(13327) About Me  (Show Source):
You can put this solution on YOUR website!


Given: x+y=66; xy=9

Find: x%5E2-y%5E2

x%5E2-y%5E2=%28x%2By%29%28x-y%29=66%28x-y%29



x%5E2-y%5E2=%2866%29%2812sqrt%2830%29%29=792sqrt%2830%29


Answer by MathTherapy(10806) About Me  (Show Source):

Question 316943: simplify: sqrt (121) / (9)
a) sqrt (11) / sqrt (3)
b) 3 sqrt (11)
c) 11/3
d) sqrt (11) / (3)

Answer by MathTherapy(10806) About Me  (Show Source):
You can put this solution on YOUR website!
simplify: sqrt (121) / (9)

a) sqrt (11) / sqrt (3)
b) 3 sqrt (11)
c) 11/3
d) sqrt (11) / (3)
******************
The other person's answer, "...d because the sqrt of 121 is 11 and the sqrt of 9 is 3," is PARTIALLY WRONG!

If it's sqrt%28121%2F9%29, then it's matrix%281%2C3%2C+sqrt%28121%29%2Fsqrt%289%29+=+11%2F3%2C+%22%28CHOICE%22%2C+%22c%29%22%29

If it's sqrt%28121%29%2F9, then it's matrix%281%2C3%2C+11%2F9%2C+%22%28no%22%2C+%22match%29%22%29


Question 1030250: I need help simplifying this expression:
sqrt%2824%2B8sqrt%285%29%29
I removed the common factor out of the square root to obtain 2sqrt%286%2B2sqrt%285%29%29, but the answer key says it is 2%2B2sqrt%285%29.
How is it possible? Am I missing out on a rule here?

Found 2 solutions by greenestamps, MathTherapy:
Answer by greenestamps(13327) About Me  (Show Source):
You can put this solution on YOUR website!


Consider this patern:

%28sqrt%28a%29%2Bsqrt%28b%29%29%5E2=%28a%2Bb%29%2B2sqrt%28ab%29

Given an expression to be simplified in the form sqrt%28a%2Bb%2Asqrt%28c%29%29, if you can modify the expression so the coefficient "b" on the inside radical is 2, then the expression can be simplified using that pattern.

In your example, you can take "4" out of the coefficient "8", leaving the required coefficient "2"; the "4" goes back inside the radical as sqrt%2816%29:

sqrt%2824%2B8sqrt%285%29%29=sqrt%2824%2B2sqrt%2816%2A5%29%29=sqrt%2824%2B2sqrt%2880%29%29

The pattern now says you want to find integers a and b for which a+b=24 and ab=80. Those integers are 20 and 4, so




Answer by MathTherapy(10806) About Me  (Show Source):
You can put this solution on YOUR website!
I need help simplifying this expression:
sqrt%2824%2B8sqrt%285%29%29
I removed the common factor out of the square root to obtain 2sqrt%286%2B2sqrt%285%29%29, but the answer key says it is 2%2B2sqrt%285%29.
How is it possible? Am I missing out on a rule here?
*************************************
This happens to be one of those RARE cases when you can actually factor out a COMMON factor, which happens to be a
PERFECT SQUARE (in 4). This is what you did:
sqrt%2824+%2B+8sqrt%285%29%29 = sqrt%284%286+%2B+2sqrt%285%29%29%29 
                            sqrt%284%29+%2A+sqrt%286+%2B+2sqrt%285%29%29 ----- Applying sqrt%28m%2An%29 = sqrt%28m%29sqrt%28n%29         
                               2sqrt%286+%2B+2sqrt%285%29%29....At this point, you haven't fully simplified the
                                                       expression, and should've continued as follows:  
                            
                   2sqrt%285+%2B+1+%2B+2sqrt%285%2A1%29%29 ---- Changing 6 to 5 + 1, and 5 to 5*1  
                    2sqrt%285+%2B+1+%2B+2sqrt%285%29sqrt%281%29%29 ---- Applying sqrt%28m%2An%29 = sqrt%28m%29sqrt%28n%29         
   2sqrt%28%28sqrt%285%29%29%5E2+%2B+%28sqrt%281%29%29%5E2+%2B+2sqrt%285%29sqrt%281%29%29 --- Converting 
The above is in the form: %28a+%2B+b%29%5E2, with system%28matrix%282%2C3%2C+a%2C+being%2C+sqrt%285%29%2C+b%2C+being%2C+sqrt%281%29%29%29, and so:
2sqrt%28%28sqrt%285%29%29%5E2+%2B+%28sqrt%281%29%29%5E2+%2B+2sqrt%285%29sqrt%281%29%29 then becomes: 2sqrt%28%28sqrt%285%29+%2B+sqrt%281%29%29%5E2%29 
                                                                                2%28sqrt%285%29+%2B+sqrt%281%29%29 ----- Cancelling SQUARE and SQUARE ROOT
                                                                                2%28sqrt%285%29+%2B+1%29 = highlight%282sqrt%285%29+%2B+2%29
                                    This certainly matches the answer key: 2%2B2sqrt%285%29
=====
On the other hand, this author would've SIMPLIFIED the SURD from the onset, as follows:
                                 sqrt%2824+%2B+8sqrt%285%29%29
                       sqrt%2824+%2B+2%284%29sqrt%285%29%29 ----- Replacing 8 with factors, 2 & 4
                         sqrt%2824+%2B+2sqrt%2816%29sqrt%285%29%29 ----- Converting 4 to sqrt%2816%29
                              sqrt%2824+%2B+2sqrt%2880%29%29 ----- Applying sqrt%28m%29sqrt%28n%29 = sqrt%28mn%29%29
                        sqrt%2824+%2B+2sqrt%2820%2A4%29%29                
                    sqrt%2820+%2B+4+%2B+2sqrt%2820%29sqrt%284%29%29 ---- Changing 24 to 20 + 4, and applying sqrt%28m%2An%29 = sqrt%28m%29sqrt%28n%29           
  sqrt%28%28sqrt%2820%29%29%5E2+%2B+%28sqrt%284%29%29%5E2+%2B+2sqrt%2820%29sqrt%284%29%29 ---- Converting 
The above is in the form: %28a+%2B+b%29%5E2, with system%28matrix%282%2C3%2C+a%2C+being%2C+sqrt%2820%29%2C+b%2C+being%2C+sqrt%284%29%29%29, and so:
    sqrt%28%28sqrt%2820%29%29%5E2+%2B+%28sqrt%284%29%29%5E2+%2B+2sqrt%2820%29sqrt%284%29%29 then becomes:      sqrt%28%28sqrt%2820%29+%2B+sqrt%284%29%29%5E2%29
                                                                                                 sqrt%2820%29+%2B+sqrt%284%29 ----- Cancelling SQUARE and SQUARE ROOT
                                                                                                 highlight%282sqrt%285%29+%2B+2%29
                              This certainly matches the answer key: 2%2B2sqrt%285%29


Question 973976: what is (4- square root of 8) divided by (2+ square root of 8) simplified

Answer by MathTherapy(10806) About Me  (Show Source):
You can put this solution on YOUR website!
what is (4- square root of 8) divided by (2+ square root of 8) simplified
*********************************************

According to the other person, "I put this into the calculator at Mathway.com, and it comes out as:
−4+3√2 (that's "three square root two")." 

Is this really "HELP?" Punching numbers on a calculator? Or, is this OUTRIGHT LAZINESS?

%284+-+sqrt%288%29%29%2F%282+%2B+sqrt%288%29%29
%284+-+sqrt%288%29%29%2F%282+%2B+sqrt%288%29%29 * %282+-+sqrt%288%29%29%2F%282+-+sqrt%288%29%29 ---- Multiplying NUMERATOR and DENOMINATOR by 2+-+sqrt%288%29, the DENOMINATOR'S conjugate
%284+-+sqrt%288%29%29%282+-+sqrt%288%29%29%2F%282+%2B+sqrt%288%29%29%2F%282+-+sqrt%288%29%29
 
        %288+-+6sqrt%288%29+%2B+8%29%2F%284+-+8%29
        %2816+-+12sqrt%282%29%29%2F%28-+4%29 ---- Converting 6sqrt%288%29 to 12sqrt%282%29
    %28-+4%28-+4+%2B+3sqrt%282%29%29%29%2F%28-+4%29 
    %28cross%28-+4%29%28-+4+%2B+3sqrt%282%29%29%29%2F%28cross%28-+4%29%29 = highlight%28-+4+%2B+3sqrt%282%29%29


Question 78896: please help me simplify this problem?
sqrt75a%5E2/sqrt5

Found 3 solutions by ikleyn, timofer, MathTherapy:
Answer by ikleyn(53748) About Me  (Show Source):
You can put this solution on YOUR website!
.
please help me simplify this problem?
sqrt%2875%2Aa%5E2%29%2Fsqrt%285%29
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


The right way to simplify is THIS

        sqrt%2875%2Aa%5E2%29%2Fsqrt%285%29 = sqrt%2815a%5E2%29 = abs%28a%29%2Asqrt%2815%29 = sqrt%2815%29%2Aabs%28a%29.         ANSWER


                Solved completely and correctly.


According to commonly accepted agreements about square root,
the expression  ' a%5E2 '  always goes from the square root as  |a|,  the absolute value of  'a'.

In this form,  this transformation works universally for positive and negative values of  ' a '.

The given problem is a standard  TRAP  to catch  highlight%28highlight%28millions%29%29  of those,  who are unfamiliar with this trap for advance.

My post shows and teaches a standard way to avoid this trap.


As tutor @MathTherapy likes to say,  " do not accept any other answer ".



Answer by timofer(155) About Me  (Show Source):
Answer by MathTherapy(10806) About Me  (Show Source):
You can put this solution on YOUR website!
please help me simplify this problem?
sqrt75a%5E2/sqrt5
*************************************
The other person wrote, "Now, you need to see that 75=5%2A4%2A4, so you can also pull out a 4 from under the radical"
How does this make sense? In what universe is 75=5%2A4%2A4? As a result, his answer, 4a is obviosly WRONG!!

highlight%28sqrt%2875a%5E2%29%2Fsqrt%285%29%29 = sqrt%2875a%5E2%2F5%29 = sqrt%2815a%5E2%29 = highlight%28matrix%281%2C4%2C+a%2Asqrt%2815%29%2C%22%2C%22%2C+or%2C+sqrt%2815%29a%29%29


Question 669305: Please help me simplify this: sqrt(x^4y^7)
Answer by MathTherapy(10806) About Me  (Show Source):
You can put this solution on YOUR website!
Please help me simplify this: sqrt(x^4y^7)
*************************************
The other person's answer, highlight_green%28x%5E2y%5E2sqrt%28y%5E3%29%29, is WRONG as he/she failed to SIMPLIFY this expression, completely. 

highlight%28sqrt%28x%5E4y%5E7%29%29 = sqrt%28%28x%5E2%29%5E2%28y%5E3%29%5E2y%29%29 = highlight%28x%5E2y%5E3sqrt%28y%29%29


Question 60849: solve for x by using the quadratic formula: 9x^2-6x+5=0
thanks so much

Answer by ikleyn(53748) About Me  (Show Source):
You can put this solution on YOUR website!
.
solve for x by using the quadratic formula: 9x^2-6x+5=0
thanks so much
~~~~~~~~~~~~~~~~~~~~~~~

        The solution by @jai_kos is incorrect.
        See my correct solution below.


9x^2-6x+5=0

It is the quadratic equation of the form.

ax^2+bx +c =0

Comparing the equations, we get
a = 9, b = -6 and c = 5

x = %28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+

x = %28-%28-6%29+%2B-+sqrt%28+%28-6%29%5E2-4%2A9%2A5+%29%29%2F%282%2A9%29+

x = %286+%2B-+sqrt%28+36-180+%29%29%2F18+

x = %286+%2B-+sqrt%28-144%29%29%2F18+

x = %286+%2B-+12i%29%2F18+ = %281+%2B-+2i%29%2F3.

Thus the given equation has no real solutions.
It has two conjugate solutions in complex numbers.

Solved correctly.




Question 60848: help on this please,,thanks
x+1= sqrt x+7

Answer by ikleyn(53748) About Me  (Show Source):
You can put this solution on YOUR website!
.
help on this please,, thanks
x+1= sqrt(x+7)
~~~~~~~~~~~~~~~~~~~~~~~~


        The solution in the post by @jai_kos is incorrect.
        See my correct solution below.


x+1= sqrt(x+7)

Square on both sides, we get

(x+1)^2 = x +7
x^2 + 2x + 1 = x + 7

Reduce it to the standard form quadratic equation

x^2 + x - 6 = 0

Factor left side

(x+3)*(x-2) = 0

The roots of this equation are x = -3 and x = 2.
Direct check shows that x = 2 is the solution to the original equation, while x = -3 is an EXTRANEOUS solution.


ANSWER. The given equation has a unique solution in real numbers x = 2.


Solved correctly.




Question 681800: I'm trying to prove that
sqrt%284+-+2+%2A+sqrt%283%29%29+%2B+sqrt%2812+-+6+%2A+sqrt%283%29%29+=+2

Answer by MathTherapy(10806) About Me  (Show Source):
You can put this solution on YOUR website!
I'm trying to prove that

sqrt%284+-+2+%2A+sqrt%283%29%29+%2B+sqrt%2812+-+6+%2A+sqrt%283%29%29+=+2            
*******************
This author's proof is different from the one the other person who responded, provided. His method
may not be what the person who needs help, is looking for. Then again, this hunch may be WRONG!

Having said that, let's focus on the L.H.S. because that's what's needed to be proven to equal 2.
                        sqrt%284+-+2sqrt%283%29%29 + sqrt%2812+-+6sqrt%283%29%29
                        sqrt%284+-+2sqrt%283%29%29 + sqrt%2812+-+2%283%29sqrt%283%29%29 ---- Changing 6 to 2(3)
                        sqrt%284+-+2sqrt%283%29%29 + sqrt%2812+-+2sqrt%289%29sqrt%283%29%29 ------- Changing 3 to sqrt%289%29 
               sqrt%283+%2B+1+-+2sqrt%283%29sqrt%281%29%29 + sqrt%289+%2B+3+-+2sqrt%289%29sqrt%283%29%29 ----- Changing 4 to 3 + 1, 3 to sqrt%283%29sqrt%281%29, and 12 to 9 + 3                 
sqrt%28%28sqrt%283%29%29%5E2+%2B+%28sqrt%281%29%29%5E2+-+2sqrt%283%29sqrt%281%29%29 + sqrt%28%28sqrt%289%29%29%5E2+%2B+%28sqrt%283%29%29%5E2+-+2sqrt%289%29sqrt%283%29%29 ------ Converting 
The above is in the form:
                          %28a%5B1%5D+-+b%5B1%5D%29%5E2  + %28a%5B2%5D+-+b%5B2%5D%29%5E2, with , and so:
sqrt%28%28sqrt%283%29%29%5E2+%2B+%28sqrt%281%29%29%5E2+-+2sqrt%283%29sqrt%281%29%29 + sqrt%28%28sqrt%289%29%29%5E2+%2B+%28sqrt%283%29%29%5E2+-+2sqrt%289%29sqrt%283%29%29 then becomes:
                   sqrt%28%28sqrt%283%29+-+sqrt%281%29%29%5E2%29 +  sqrt%28%28sqrt%289%29+-+sqrt%283%29%29%5E2%29
                         sqrt%283%29+-+sqrt%281%29    +    sqrt%289%29+-+sqrt%283%29 ----- Cancelling SQUARE and SQUARE ROOT
                             sqrt%283%29+-+1 + 3+-+sqrt%283%29+=+highlight%282%29%29QED!


Question 1107093: One pair of integers (x.y) solves +sqrt%28+4%2Asqrt%28+7+%29%2B11+%29=y%2Bsqrt%28+x+%29+, find x*y.
Answer by MathTherapy(10806) About Me  (Show Source):
You can put this solution on YOUR website!
One pair of integers (x.y) solves +sqrt%28+4%2Asqrt%28+7+%29%2B11+%29=y%2Bsqrt%28+x+%29+, find x*y.
***************************************************************
                              sqrt%284sqrt%287%29+%2B+11%29%29
                              sqrt%2811+%2B+4sqrt%287%29%29
                    sqrt%2811+%2B+2%282%29sqrt%287%29%29 ----- Replacing 4 with its PRIME factors, 2 & 2
                         sqrt%2811+%2B+2sqrt%284%29sqrt%287%29%29 ----- Converting 2 to sqrt%284%29                 
                      sqrt%287+%2B+4+%2B+2sqrt%287%29sqrt%284%29%29 ---- Changing 11 to 7 + 4             
     sqrt%28%28sqrt%287%29%29%5E2+%2B+%28sqrt%284%29%29%5E2+%2B+2sqrt%287%29sqrt%284%29%29 ---- Converting 
The above is in the form: %28a+%2B+b%29%5E2, with system%28matrix%282%2C3%2C+a%2C+being%2C+sqrt%287%29%2C+b%2C+being%2C+sqrt%284%29%29%29, and so:
sqrt%28%28sqrt%287%29%29%5E2+%2B+%28sqrt%284%29%29%5E2+%2B+2sqrt%287%29sqrt%284%29%29 then becomes: sqrt%28%28sqrt%287%29+%2B+sqrt%284%29%29%5E2%29 
                                                                                sqrt%287%29+%2B+sqrt%284%29 ----- Cancelling SQUARE and SQUARE ROOT
                                                                                sqrt%287%29+%2B+2

√(4√(7+11)) = sqrt%287%29+%2B+2, is in the form: y + √x, with y = 2, and x = 7. Therefore, x*y = 7(2) = 14. 


Question 1124474: How would you simplify the equation:
Sqrt(17-12sqrt2) in the form
(a+bsqrt2)
Thank you.

Answer by MathTherapy(10806) About Me  (Show Source):
You can put this solution on YOUR website!
How would you simplify the equation:
Sqrt(17-12sqrt2) in the form
(a+bsqrt2)
Thank you. 
**********************************
Not an equation, but an expression, instead!!
                           sqrt%2817+-+12sqrt%282%29%29
                    sqrt%2817+-+2%286%29sqrt%282%29%29 ----- Changing 12 to 2*6
                     sqrt%2817+-+2sqrt%2836%29sqrt%282%29%29 ------ Converting 6 to sqrt%2836%29
                         sqrt%2817+-+2sqrt%2872%29%29 ------ Applying sqrt%28m%29sqrt%28n%29+=+sqrt%28mn%29
                  sqrt%289+%2B+8+-+2%289%2A8%29%29 ----- Changing 17 to 9 + 8, and 72 (in sqrt%2872%29) to 9*8
                    sqrt%289+%2B+8+-+2sqrt%289%29sqrt%288%29%29 ------ Applying sqrt%28m%2An%29+=+sqrt%28m%29sqrt%28n%29
  sqrt%28%28sqrt%289%29%29%5E2+%2B+%28sqrt%288%29%29%5E2+-+2sqrt%289%29sqrt%288%29%29 ------ Converting 
The above is in the form: %28a+-+b%29%5E2, with system%28matrix%282%2C3%2C+a%2C+being%2C+sqrt%289%29%2C+b%2C+being%2C+sqrt%288%29%29%29, and so:
sqrt%28%28sqrt%289%29%29%5E2+%2B+%28sqrt%288%29%29%5E2+-+2sqrt%289%29sqrt%288%29%29 then becomes: sqrt%28%28sqrt%289%29+-+sqrt%288%29%29%5E2%29 
                                                                                sqrt%289%29+-+sqrt%288%29 ----- Cancelling SQUARE and SQUARE ROOT
                                                                                highlight%283+-+2sqrt%282%29%29


Question 263259: solve: x^5/6 + x^2/3-2x^1/2 =0
thanks!

Answer by ikleyn(53748) About Me  (Show Source):
You can put this solution on YOUR website!
.
solve: x^5/6 + x^2/3 - 2x^1/2 = 0
~~~~~~~~~~~~~~~~~~~~~~~~~


        The solution in the post by @mananth is FATALLY incorrect.

        His first step is to raise all three addends in the left side of the equation to degree 6.
        But this step is not an equivalent transformation, so, starting from this point,
        his solution is inadequate.

        See my correct solution below.


The original equation is 

    x^5/6 + x^2/3 - 2x^1/2 = 0.      (1)


It is the same as

    x^5/6 + x^4/6 - 2x^3/6 = 0.      (2)


Factor left side, taking  x^3/6  out the parentheses as a common factor

    x^3/6*(x^2/6 + x^1/6 - 2) = 0.   (3)


One root is  x = 0,  generated by the common factor  x^3/6.


To find the roots generated by the expression in parentheses, introduce new variable  t = x^1/6.


Then the expression in parentheses is 

    t^2 + r - 2.


Its roots are  t%5B1%2C2%5D = %28-1+%2B-+sqrt%281+-+4%2A1%2A%28-2%29%29%29%2F2 = %28-1+%2B-+sqrt%281%2B8%29%29%2F2 = %28-1+%2B+sqrt%289%29%29%2F2 = %28-1+%2B-+3%29%2F2.


So, the roots are t = -2 and  t = 1.   


Since t = x^1/6,  we accept the positive root  t = 1  and  reject the negative root t = -2.


Thus, finally we have the solutions to the original equation  x = 0  and  x = 1.


ANSWER.  The original equation has two real solutions  x = 0  and  x = 1.

Solved correctly.




Question 1094302: Solving by substitution with u
+x%5E2-3x-sqrt%28x%5E2-3x%29=2+
+u+=+sqrt%28x%5E2-3x%29+
+u%5E2+=+sqrt%28x%5E2-3x%29+=+x%5E2-3x+
creates quadratic = +u%5E2-u+=+2+
+u%5E2-u-2=0+
+%28u-2%29%28u%2B1%29+
u = 2,-1
going back and using those two outputs in +sqrt%28x%5E2-3x%29+
+sqrt%28%282%29%5E2-3%282%29%29+ and +sqrt%28%28-1%29%5E2-3%28-1%29%29+
+sqrt%284-6%29+ and +sqrt%281%2B3%29+
Finally, I get +sqrt%28-2%29+ and +sqrt%284%29+
But -2 can't be in a radical and would 4 turn into 2,-2 or just 2?

Answer by MathTherapy(10806) About Me  (Show Source):
You can put this solution on YOUR website!
Solving by substitution with u
+x%5E2-3x-sqrt%28x%5E2-3x%29=2+

+u+=+sqrt%28x%5E2-3x%29+
+u%5E2+=+sqrt%28x%5E2-3x%29+=+x%5E2-3x+
creates quadratic = +u%5E2-u+=+2+
+u%5E2-u-2=0+
+%28u-2%29%28u%2B1%29+
u = 2,-1
going back and using those two outputs in +sqrt%28x%5E2-3x%29+
+sqrt%28%282%29%5E2-3%282%29%29+ and +sqrt%28%28-1%29%5E2-3%28-1%29%29+
+sqrt%284-6%29+ and +sqrt%281%2B3%29+
Finally, I get +sqrt%28-2%29+ and +sqrt%284%29+

But -2 can't be in a radical and would 4 turn into 2,-2 or just 2? 
******************************************************************

u = 2,-1 <=== This is okay!
"going back and using those two outputs in +sqrt%28x%5E2-3x%29+    +sqrt%28%282%29%5E2-3%282%29%29+ and +sqrt%28%28-1%29%5E2-3%28-1%29%29+ <=== Here's where I guess 
                                                                                                                you got confused, and substituted 2 and - 1 for x in sqrt%28x%5E2-3x%29

But, u = 2, as you mentioned above, NOT x = 2. And, because you'd substituted u for sqrt%28x%5E2+-+3x%29 earlier, at this juncture, you
need to BACK-SUBSTITUTE the value of u to get:
                      2+=+sqrt%28x%5E2+-+3x%29 
                   2%5E2+=+%28sqrt%28x%5E2+-+3x%29%29%5E2 ---- Squaring both sides
                    4+=+x%5E2+-+3x
     x%5E2+-+3x+-+4+=+0
(x - 4)(x + 1) = 0
  x - 4 = 0          OR        x + 1 = 0
       x = 4           OR              x = - 1 

Now, you have 2 values for x that you can CHECK to ensure that they're VALID and NOT EXTRANEOUS. 

Also, u = - 1, as you mentioned above. And, because you'd substituted u for sqrt%28x%5E2+-+3x%29 earlier, at this juncture, you need 
to BACK-SUBSTITUTE the value of u to get: -+1+=+sqrt%28x%5E2+-+3x%29 
Seeing that the square root of ANY expression is positive (> 0), it's obvious that u = - 1 is an EXTRANEOUS value. As such,
x = 4, or x = - 1 (see above). 


Question 569284: solve the following radical: +sqrt+%28+3x+%29%2B+sqrt+%28+2x-1+%29+=+5+%2F+sqrt+%28+2x-1+%29+
Answer by MathTherapy(10806) About Me  (Show Source):
You can put this solution on YOUR website!
solve the following radical: +sqrt+%28+3x+%29%2B+sqrt+%28+2x-1+%29+=+5+%2F+sqrt+%28+2x-1+%29+
**********************************************<

Just like "Rational-functions/875226", - 12 is NOT a solution. It's an 
EXTRANEOUS root. Only VALID and ACCEPTABLE answer: highlight%28x+=+3%2F2%29


Question 864099: Can you show me how to Rationalize the denominator and simply the equation
6 / the square root of 2 - the square root of 3.

Answer by MathTherapy(10806) About Me  (Show Source):
You can put this solution on YOUR website!
Can you show me how to Rationalize the denominator and simply the equation 
6 / the square root of 2 - the square root of 3.
*********************************************************************
%28highlight%28sqrt%286%29%2F%28sqrt%282%29+-+sqrt%283%29%29%29%29%28%28sqrt%282%29+%2B+sqrt%283%29%29%2F%28sqrt%282%29+%2B+sqrt%283%29%29%29 =  = %28sqrt%2812%29+%2B+sqrt%2818%29%29%2F%282+-+3%29 = 


Question 864097: Can you show me how to Rationalize the denominator and simply the equation the square root of 6 / the square root of 5 - the square root of 3.
Answer by MathTherapy(10806) About Me  (Show Source):
You can put this solution on YOUR website!
Can you show me how to Rationalize the denominator and simply the equation
the square root of 6 / the square root of 5 - the square root of 3.
*********************************************************************
%28highlight%28sqrt%286%29%2F%28sqrt%285%29+-+sqrt%283%29%29%29%29%28%28sqrt%285%29+%2B+sqrt%283%29%29%2F%28sqrt%285%29+%2B+sqrt%283%29%29%29 =  = %28sqrt%2830%29+%2B+sqrt%2818%29%29%2F%285+-+3%29 = highlight%28%28sqrt%2830%29+%2B+3sqrt%282%29%29%2F2%29


Question 707329: How would you solve this equation?
+sqrt+%28+2x+%29+=+sqrt+%28+3x%2B12+%29-2+

Answer by MathTherapy(10806) About Me  (Show Source):
You can put this solution on YOUR website!
How would you solve this equation?

+sqrt+%28+2x+%29+=+sqrt+%28+3x%2B12+%29-2+
**************************************
The other person's response, that "You get -10+6i or -10-6i (complex results)", is WRONG11

sqrt%282x%29+=+sqrt%283x%2B12%29+-+2
As the smaller radicand, 2x MUST be greater than or equal to 0, we get: 2x+%3E=+0. So, x+%3E=+0.  
This gives us:      sqrt%282x%29+=+sqrt%283x%2B12%29+-+2, with x+%3E=+0
                         %28sqrt%282x%29%29%5E2+=+%28sqrt%283x+%2B+12%29+-+2%29%5E2 ---- Squaring both sides
                               2x+=+3x+%2B+12+-+4sqrt%283x+%2B+12%29+%2B+4
                    4sqrt%283x+%2B+12%29+=+3x+%2B+12+%2B+4+-+2x
                    4sqrt%283x+%2B+12%29+=+x+%2B+16
                  16%283x+%2B+12%29+=+x%5E2+%2B+32x+%2B+256 ----- Squaring both sides
                     48x+%2B+192+=+x%5E2+%2B+32x+%2B+256
x%5E2+%2B+32x+%2B+256+-+48x+-+192+=+0
                 x%5E2+-+16x+%2B+64+=+0
                        %28x+-+8%29%5E2+=+0
                          x - 8 = 0.
                               highlight%28x+=+8%29 <==== VALID, and ACCEPTABLE solution for x, in THIS case!!


Question 144143: Hello. Please help me solve this problem: I need to find the simplest radical form and the approximate answer of sqrt+%285%29-1%2Fx+=+sqrt+%285%29%2F2.
2%28sqrt%285%29-2%2Fx=sqrt%285%29
sqrt%285%29-2%2Fx=0
sqrt%285%29=2%2Fx
x%28sqrt%285%29%29=2
x=2%2Fsqrt%285%29
x = 0.8944

Answer by MathTherapy(10806) About Me  (Show Source):
You can put this solution on YOUR website!
Hello. Please help me solve this problem: 
I need to find the  simplest radical form and the approximate answer of sqrt+%285%29-1%2Fx+=+sqrt+%285%29%2F2.
2%28sqrt%285%29-2%2Fx=sqrt%285%29
sqrt%285%29-2%2Fx=0
sqrt%285%29=2%2Fx
x%28sqrt%285%29%29=2
x=2%2Fsqrt%285%29
x = 0.8944
*****************
         sqrt%285%29+-+1%2Fx+=+sqrt%285%29%2F2
    2x%2Asqrt%285%29+-+2+=+x%2Asqrt%285%29 ---- Multiplying by LCD, 2x
2x%2Asqrt%285%29+-+x%2Asqrt%285%29+=+2 
          x%2Asqrt%285%29+=+2
      %28x%2Asqrt%285%29%29%5E2+=+2%5E2 ----- Squaring each side
       x%5E2%285%29+=+4
           x%5E2+=+4%2F5
            

However, the negative x-value, -2sqrt%285%29%2F5 is EXTRANEOUS, therefore leaving the sole VALID x-value, highlight%282sqrt%285%29%2F5%29. 

Great job!! You got up to this point: x=2%2Fsqrt%285%29, but needed to go a little further, by RATIONALIZING the
DENOMINATOR, as demonstrated above. Your decimal approximation, x = 0.8944, is also CORRECT.
I don't know why you sought help. You didn't need it!

Again, great job!!


Question 798582: Simplify if necessary. Then rationalize the denominator.
sqrt%282%2F3%29%2Asqrt%286%2F22%29

Answer by MathTherapy(10806) About Me  (Show Source):
You can put this solution on YOUR website!
Simplify if necessary. Then rationalize the denominator.

sqrt%282%2F3%29%2Asqrt%286%2F22%29
**************************

CORRECT answer: highlight%282sqrt%2811%29%2F11%29, or highlight%28%282%2F11%29sqrt%2811%29%29, and NOT sqrt%282%2F11%29 as the other person states.


Question 459722: Simplify each expression by rationalizing the denominator.
3/sqrt(7)
2sqrt(2)/sqrt(5)
3sqrt(2)/sqrt(6)
2sqrt(5)/sqrt(12)

Answer by MathTherapy(10806) About Me  (Show Source):
You can put this solution on YOUR website!
Simplify each expression by rationalizing the denominator.
3/sqrt(7)
2sqrt(2)/sqrt(5)
3sqrt(2)/sqrt(6)
2sqrt(5)/sqrt(12)
******************

This problem "asks" to SIMPLIFY by "rationalizing the denominator," NOT providing a calculated value, as the other person did!

      , or highlight%28%283%2F7%29sqrt%287%29%29

, or highlight%28%282%2F5%29sqrt%2810%29%29



, or highlight%28%281%2F3%29sqrt%2815%29%29


Question 904562: sqrt%284x%2B1%29-sqrt%282x%2B4%29=1
Answer by MathTherapy(10806) About Me  (Show Source):
You can put this solution on YOUR website!
sqrt%284x%2B1%29-sqrt%282x%2B4%29=1
*****************************
It is UNBELIEVABLE that the person who responded to this problem applied this RIDICULOUS approach. 

The person got up to x%5E2+-+6x+=+0, and UNBELIEVABLY, HE chose to, "complete the squares........"
What would behoove someone to suggest such a thing to a person who asks for help with a math problem?
Now, isn't x%5E2+-+6x+=+0 SIMPLY x(x - 6) = 0, which results in values of 0 and 6 for x? Why would someone
go through all that trouble to COMPLETE the SQUARE here? It's the same as using the quadratic equation formula
to solve it, which is EXTREMELY RIDICULOUS and TOTALLY UNNECESSARY.....a TOTAL waste of time, in this author's
opinion. Some people are probably more eccentric than is realized!!


Question 296793: Please help me solve this equation
4%2Bsqrt%2810-x%29=6%2Bsqrt%284-x%29

Answer by MathTherapy(10806) About Me  (Show Source):
You can put this solution on YOUR website!
Please help me solve this equation
4%2Bsqrt%2810-x%29=6%2Bsqrt%284-x%29
******************************
This is UTTERLY CRAZY!! Who ever heard of this: 4%2Bsqrt%2810-x%29=6%2Bsqrt%284-x%29 square everything
4%5E2%2B%28sqrt%2810-x%29%29%5E2=6%5E2%2B%28sqrt%284-x%29%29%5E2 <=== Who in their right mind would square both sides of a square root problem like this? Why do
these people respond in this manner? This "HELP" is NO HELP at all!! Just leave the problem for someone who can handle it!
BTW, the person claimed this to be an UNDEFINED equation. In other words, there are no solutions! Really!! Ha-ha-ha! 

 4+%2B+sqrt%2810+-+x%29+=+6+%2B+sqrt%284+-+x%29
    sqrt%2810+-+x%29+=+2+%2B+sqrt%284+-+x%29
 %28sqrt%2810+-+x%29%29%5E2+=+%282+%2B+sqrt%284+-+x%29%29%5E2 --- Squaring BOTH sides, the CORRECT way
      10+-+x+=+4+%2B+4sqrt%284+-+x%29+%2B+4+-+x
10+-+8+-+x+%2B+x+=+4sqrt%284+-+x%29
         2+=+4sqrt%284+-+x%29
         1+=+2sqrt%284+-+x%29 ---- Dividing by GCF, 2
         1 = 4(4 - x) --- Squaring each side
         1 = 16 - 4x
    1 - 16 = - 4x
      - 15 = - 4x
    %28-+15%29%2F%28-+4%29+=+highlight%2815%2F4+=+x%29

This x-value, 15%2F4 is VALID!!


Question 37745: Hi, I'm having trouble with this problem. Do you think you could help me?
+sqrt+6x%5E3++%2A++sqrt+150x%5E2+

Answer by MathTherapy(10806) About Me  (Show Source):
You can put this solution on YOUR website!
Hi, I'm having trouble with this problem. Do you think you could help me? 
+sqrt+6x%5E3++%2A++sqrt+150x%5E2+
***********************************************************************
Correct answer: highlight%2830x%5E2sqrt%28x%29%29, and NOT x%5E2sqrt%2830x%29 as the other person states!


Question 729072: square root of x+7=square root of 2x-3 (+2) not under the square root)
Answer by MathTherapy(10806) About Me  (Show Source):
You can put this solution on YOUR website!
square root of x+7=square root of 2x-3    (+2) not under the square root)
*************************************************************************
I don't know what "X=507+338√2 ≈985.0042 from @lynnlo(4176) is all about.

square root of x+7=square root of 2x-3    (+2) not under the square root)
              sqrt%28x+%2B+7%29+=+sqrt%282x+-+3%29+%2B+2
            %28sqrt%28x+%2B+7%29%29%5E2+=+%28sqrt%282x+-+3%29+%2B+2%29%5E2 --- Squaring both sides
                x+%2B+7+=+2x+-+3+%2B+4sqrt%282x+-+3%29+%2B+4 
                x+%2B+7+=+2x+%2B+4sqrt%282x+-+3%29+%2B+1
         x+%2B+7+-+2x+-+1+=+4sqrt%282x+-+3%29
              -+x+%2B+6+=+4sqrt%282x+-+3%29
            %28-+x+%2B+6%29%5E2+=+%284sqrt%282x+-+3%29%29%5E2 ----- Squaring both sides
         x%5E2+-+12x+%2B+36+=+16%282x+-+3%29
         x%5E2+-+12x+%2B+36+=+32x+-+48
x%5E2+-+12x+%2B+36+-+32x+%2B+48+=+0
         x%5E2+-+44x+%2B+84+=+0
     (x - 42)(x - 2) = 0
      x - 42 = 0      OR     x - 2 = 0
           x = 42     OR         x = 2

However, x = 42 is an EXTRANEOUS solution, so ONLY solution is: x = 2


Question 519668: how do you solve the following:
sqrt%28x%2B4%29 + sqrt%282x-1%29 = sqrt%287x%2B1%29

Answer by MathTherapy(10806) About Me  (Show Source):
You can put this solution on YOUR website!
how do you solve the following:

sqrt%28x%2B4%29 + sqrt%282x-1%29 = sqrt%287x%2B1%29
******************************
One of the persons who responded states that x+=+-+1%2F2, but this is WRONG!! x CANNOT equal -+1%2F2.

Of the 3 RADICAL expressions, 2x - 1 is the SMALLEST. So, 2x+-+1+%3E=+0, and 2x+%3E=+1 ===> x+%3E=+1%2F2.
  So, we now get: sqrt%28x+%2B+4%29 + sqrt%282x+-+1%29 = sqrt%287x+%2B+1%29, with x+%3E=+1%2F2
                  sqrt%28x+%2B+4%29 + sqrt%282x+-+1%29 = sqrt%287x+%2B+1%29
                  %28sqrt%28x+%2B+4%29+%2B+sqrt%282x+-+1%29%29%5E2 = %28sqrt%287x+%2B+1%29%29%5E2 ----- Squaring both sides
 = 7x + 1
     x+%2B+4+%2B+2sqrt%28%28x+%2B+4%29%282x+-+1%29%29+%2B+2x+-+1 = 7x + 1
              3x+%2B+3+%2B+2sqrt%282x%5E2+%2B+7x+-+4%29 = 7x + 1
                     2sqrt%282x%5E2+%2B+7x+-+4%29 = 7x + 1 - 3x - 3
                     2sqrt%282x%5E2+%2B+7x+-+4%29 = 4x - 2
                  %282sqrt%282x%5E2+%2B+7x+-+4%29%29%5E2 = %284x+-+2%29%5E2 ------ Squaring both sides
                       4%282x%5E2+%2B+7x+-+4%29+=+16x%5E2+-+16x+%2B+4
                         8x%5E2+%2B+28x+-+16+=+16x%5E2+-+16x+%2B+4
                                    0+=+16x%5E2+-+16x+%2B+4+-+8x%5E2+-+28x+%2B+16
                                    0+=+8x%5E2+-+44x+%2B+20
                                    0+=+4%282x%5E2+-+11x+%2B+5%29
                                    0+=+2x%5E2+-+11x+%2B+5
                                    0+=+2x%5E2+-+10x+-+x+%2B+5
                                    0+=+2x%28x+-+5%29+-+1%28x+-+5%29
                                    0 = (2x - 1)(x - 5) 
                                    0 = 2x - 1      OR     0 = x - 5
                                    1 = 2x          OR    5 = x
                                   highlight%281%2F2+=+x%29
As x+=+1%2F2+%3E=+1%2F2 and x+=+5+%3E=+1%2F2, both solutions for x are VALID! 


Question 701399: simplify +sqrt%2845%29-10%2Fsqrt%285%29+
Answer by MathTherapy(10806) About Me  (Show Source):
You can put this solution on YOUR website!
simplify +sqrt%2845%29-10%2Fsqrt%285%29+
====================================
The other person's answer, 15, is WRONG!!

sqrt%2845%29+-+10%2Fsqrt%285%29 = %28sqrt%2845%29%2Asqrt%285%29%29%2Fsqrt%285%29+-+10%2Fsqrt%285%29 = %28sqrt%289+%2A+5%29sqrt%285%29+-+10%29%2Fsqrt%285%29 = %28sqrt%289%29sqrt%285%29sqrt%285%29+-+10%29%2Fsqrt%285%29 = %283%285%29+-+10%29%2Fsqrt%285%29 = %2815+-+10%29%2Fsqrt%285%29 = 5%2Fsqrt%285%29 = %285%2Fsqrt%285%29%29%28sqrt%285%29%2Fsqrt%285%29%29 = 5sqrt%285%29%2F5 = cross%285%29sqrt%285%29%2Fcross%285%29 = highlight%28sqrt%285%29%29


Question 993742: Hello. I am having an issue solving this problem and I look to you for help. My problem is:
6sqrt%2812%29-8sqrt%2850%29+9sqrt%2872%29. By using prime factorization, I know that 12 = 2^2*3
50 = 5^2*2
72 = 3^2*2^3
Now, I plug these terms back in and I get:
6%2A2sqrt%283%29-8%2A5sqrt%282%29+9%2A3%2A2sqrt%282%29 If I continue, I get:
12sqrt%283%29-40sqrt%282%29+54sqrt%282%29
The answer key shows that the answer should be
57sqrt%283%29-40sqrt%282%29 Can you see where I went wrong? I'm not coming up with the right answer.

Answer by MathTherapy(10806) About Me  (Show Source):
You can put this solution on YOUR website!
Hello. I am having an issue solving this problem and I look to you for help. My problem is:

6sqrt%2812%29-8sqrt%2850%29+9sqrt%2872%29. By using prime factorization, I know that 12 = 2^2*3
            50 = 5^2*2
            72 = 3^2*2^3
Now, I plug these terms back in and I get:
6%2A2sqrt%283%29-8%2A5sqrt%282%29+9%2A3%2A2sqrt%282%29 If I continue, I get:

12sqrt%283%29-40sqrt%282%29+54sqrt%282%29
The answer key shows that the answer should be
 57sqrt%283%29-40sqrt%282%29 Can you see where I went wrong? I'm not coming up with the right answer. 
=========================
57sqrt%283%29-40sqrt%282%29 can NEVER be the simplified answer here. This answer must be for a different problem. 
Correct answer: highlight%2812sqrt%283%29+%2B+14sqrt%282%29%29
=====================================================
Hello. I am having an issue solving this problem and I look to you for help. My problem is:

6sqrt%2812%29-8sqrt%2850%29+9sqrt%2872%29. By using prime factorization, I know that 12 = 2^2*3
            50 = 5^2*2
            72 = 3^2*2^3 
Now, I plug these terms back in and I get:
6%2A2sqrt%283%29-8%2A5sqrt%282%29+9%2A3%2A2sqrt%282%29    
6%2A2sqrt%283%29-8%2A5sqrt%282%29+9%2A3%2A2sqrt%282%29 If I continue, I get: 

  12sqrt%283%29-40sqrt%282%29+54sqrt%282%29
= 12sqrt%283%29+14sqrt%282%29<==== Should be THIS, your FINAL answer!!

You ALREADY have the correct answer, as you can see.


Question 1179144: For what values of c will x² +28x + c = 0 have no real solutions? Explain
Answer by ikleyn(53748) About Me  (Show Source):
You can put this solution on YOUR website!
.
For what values of c will x^2 +28x + c = 0 have no real solutions? Explain
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


The given quadratic equation has no real solutions if and only if its discriminant is a negative value.


The discriminant is  d = 28^2 - 4c = 784 - 4c.


The condition of negativity the discriminant is

    784 - 4c < 0,   or   4c > 784,   c > 784/4 = 196.


ANSWER.  The given equation has no real solutions at c > 196.

Solved.




Question 787079: Simplify the expression. Assume that all variables are positive
√x/5*√x/20

Answer by MathTherapy(10806) About Me  (Show Source):
You can put this solution on YOUR website!
Simplify the expression.  Assume that all variables are positive

√x/5*√x/20

If %28sqrt%28x%29%2F5%29+%2A+%28sqrt%28x%29%2F20%29, then the answer is NOT 10x, as stated by the other person who responded.
%28sqrt%28x%29%2F5%29+%2A+%28sqrt%28x%29%2F20%29 = %28sqrt%28x%29+%2A+sqrt%28x%29%29%2F%285+%2A+20%29 = sqrt%28x+%2A+x%29%2F100 = sqrt%28x%5E2%29%2F100%29 = highlight%28x%2F100%29


Question 99475: Perform the indicated division. Rationalize the denominator if necessary. Then simplify each radical expression
-9-sqrt(108) dived by 3

Answer by MathTherapy(10806) About Me  (Show Source):
You can put this solution on YOUR website!
Perform the indicated division. Rationalize the denominator if necessary. Then simplify each radical expression

-9-sqrt(108) dived by 3

The answer is highlight%28-+3+-+2sqrt%283%29%29%29 (see Question # 83444), and NOT -+5sqrt%283%29 as the other person states.

%28-9-6sqrt%283%29%29%2F3+%3C%3E+%28-15sqrt%283%29%29%2F3, as he/she suggests! I wonder where these people learned their mathematics!


Question 293344: how would you solve this proof?
+%28sqrt%286%29-sqrt%282%29%29%2F4+=+sqrt%282-sqrt%283%29%29%2F2+

Answer by MathTherapy(10806) About Me  (Show Source):
You can put this solution on YOUR website!
how would you solve this proof?
+%28sqrt%286%29-sqrt%282%29%29%2F4+=+sqrt%282-sqrt%283%29%29%2F2+

This is indeed a NESTED SURD. From the other person's response, let me pick up from this point:
sqrt%288-4%2Asqrt%283%29%29+=+sqrt%286%29-sqrt%282%29+ Start with the given equation.

Let's focus on the L.H.S. of the equation.
sqrt%288+-+4sqrt%283%29%29
sqrt%288+-+2%2A2sqrt%283%29%29
sqrt%288+-+2sqrt%284%29sqrt%283%29%29 --- Converting 2 to sqrt%284%29
sqrt%288+-+2sqrt%284+%2A+3%29%29
sqrt%288+-+2sqrt%2812%29%29
sqrt%286+%2B+2+-+2sqrt%286+%2A+2%29%29 ---- Changing 8 to 6 + 2, and 12 to 6 * 2
sqrt%286+%2B+2+-+2sqrt%286%29sqrt%282%29%29
sqrt%28%28sqrt%286%29%29%5E2+%2B+%28sqrt%282%29%29%5E2+-+2sqrt%286%29sqrt%282%29%29 --- Converting 6 to %28sqrt%286%29%29%5E2 and 2 to %28sqrt%282%29%29%5E2
The above is now in the form: %28a+-+b%29%5E2, with a being sqrt%286%29, and b being sqrt%282%29
So, sqrt%28%28sqrt%286%29%29%5E2+%2B+%28sqrt%282%29%29%5E2+-+2sqrt%286%29sqrt%282%29%29 now becomes: sqrt%28%28sqrt%286%29+-+sqrt%282%29%29%29%5E2 
                                              sqrt%286%29+-+sqrt%282%29 ---- Cancelling square and sqrt
                                              highlight%28sqrt%286%29+-+sqrt%282%29%29 = highlight%28sqrt%286%29+-+sqrt%282%29%29
As seen, L.H.S. = R.H.S.


Question 485164: Write the following expression as a radical and simplify if possible.
(-64)^4/3

Answer by MathTherapy(10806) About Me  (Show Source):
You can put this solution on YOUR website!
Write the following expression as a radical and simplify if possible.
(-64)^4/3

The other person's answer, 81, is WRONG!!
highlight%28matrix%282%2C1%2C+%22+%22%2C+%28-+64%29%5E%284%2F3%29%29%29 = %28root%283%2C+-+64%29%29%5E4 = %28-+4%29%5E4+=+highlight%28256%29


Question 732218: how do you do √50x√18?
Found 2 solutions by MathTherapy, ikleyn:
Answer by MathTherapy(10806) About Me  (Show Source):
You can put this solution on YOUR website!
how do you do √50x√18?

√50 x √18 = 5√2 x 3√2 = 5(3)(√2 x √2) = 15√2 x √2 = 15√4 = 15(2) = 30

Answer by ikleyn(53748) About Me  (Show Source):
You can put this solution on YOUR website!
.
how do you do √50x√18?
~~~~~~~~~~~~~~~~~~~~~~

I treat the square roots as having positive values and 'x' as the multiplication sign.


It is what should be told in the problem's description, but since it is omitted,
I insert it to make your request sensible.


Then  sqrt%2850%29 * sqrt%2818%29 = sqrt%2850%2A18%29 = sqrt%28900%29 = 30.    ANSWER

Solved.




Question 735358: Rationalize 2 divided by 1 minus the square root of 2
Answer by ikleyn(53748) About Me  (Show Source):
You can put this solution on YOUR website!
.
Rationalize 2 divided by 1 minus the square root of 2.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

2%2F%281-sqrt%282%29%29 = %282%2F%281-sqrt%282%29%29%29%2A%28%281%2Bsqrt%282%29%29%2F%281%2Bsqrt%282%29%29%29.



In the numerator, you have  2%2A%281%2Bsqrt%282%29%29 = 2%2B2%2Asqrt%282%29.


In the denominator, you have  %281-sqrt%282%29%29%2A%281%2Bsqrt%282%29%29 = 1 - 2 = -1.


Therefore, the original fraction  2%2F%281-sqrt%282%29%29  is   -2-2sqrt%282%29.   ANSWER

Solved.

Ignore the post by @lynnlo, since it is INCORRECT.




Question 736159: I am not sure how to work this problem out. (It asks for me to show my work)
x^5*x^√

Answer by ikleyn(53748) About Me  (Show Source):
You can put this solution on YOUR website!
.
I am not sure how to work this problem out. (It asks for me to show my work)
x^5*x^√
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


As the "problem" is written, it does not make sense.

So, this collection of words and mathematical symbols is NOT a Math problem
and, THEREFORE, is NOT a subject for discussion as a Math problem at this forum.


My condolences.




Question 633567: Please help me solve, a=?, b=35, c= 37
Found 3 solutions by mccravyedwin, Edwin McCravy, ikleyn:
Answer by mccravyedwin(421) About Me  (Show Source):
You can put this solution on YOUR website!
As always, Ikleyn has to be a smarty pants. She constantly criticizes the
struggling students who post on this site.  She mainly wants to show how
clever she is, even though the clever method she uses is often not the one 
the teacher is teaching.

So now she has to criticize me for criticizing her.  Before she wrote this 
I was thinking of congratulating her for not criticizing this student for
failing to give the necessary equation. 

No, I'm not here to "show my presence". It is important to show the student 
that if the question were this,

Given a%5E2%2Bb%5E2=c%5E2, b=35, c=37, what is a?

then the answer could be a = 12 or a = -12. 

Edwin


Answer by Edwin McCravy(20077) About Me  (Show Source):
You can put this solution on YOUR website!

12 or -12

Edwin

Answer by ikleyn(53748) About Me  (Show Source):
You can put this solution on YOUR website!
.
Please help me solve, a=?, b=35, c= 37
~~~~~~~~~~~~~~~~~~~~~~~~~


I consider it as a Pythagorean equation

a^2 + b^2 = c^2,

a^2 + 35^2 = 37^2,

a^2 = 37^2 - 35^2 = (37-35)*(37+35) = 2*72 = 144,

a^2 = 144,

a = sqrt%28144%29 = 12.


--------------------------------


Looking at Edwin's post, I clearly see that Edwin wants to show his presence here,
but I don't see much point in his introducing a negative value for the quantity
representing the length of a segment.

Only so I could refute it.




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