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Complex_Numbers/195737: Multiply: (1/6 – i)^2
1 solutions

Answer 146787 by jim_thompson5910(28504) About Me  on 2009-05-10 22:55:58 (Show Source):
You can put this solution on YOUR website!

%28z-i%29%5E2 Start with the given expression.


%281%2F6-i%29%281%2F6-i%29 Expand. Remember something like x%5E2=x%2Ax.


Now let's FOIL the expression.


Remember, when you FOIL an expression, you follow this procedure:


%28highlight%281%2F6%29-i%29%28highlight%281%2F6%29-i%29 Multiply the First terms:%281%2F6%29%2A%281%2F6%29=%281%2F6%29%5E2=1%2F36.


%28highlight%281%2F6%29-i%29%28z%2Bhighlight%28-i%29%29 Multiply the Outer terms:%281%2F6%29%2A%28-i%29=-%281%2F6%29%2Ai.


%281%2F6%2Bhighlight%28-i%29%29%28highlight%281%2F6%29-i%29 Multiply the Inner terms:%28-i%29%2A%281%2F6%29=-%281%2F6%29%2Ai.


%281%2F6%2Bhighlight%28-i%29%29%281%2F6%2Bhighlight%28-i%29%29 Multiply the Last terms:%28-i%29%2A%28-i%29=i%5E2=-1.


---------------------------------------------------
So we have the terms: 1%2F36, -%281%2F6%29%2Ai, -%281%2F6%29%2Ai, and -1


1%2F36-%281%2F6%29%2Ai-%281%2F6%29%2Ai-1 Now add every term listed above to make a single expression.


-35%2F36-%281%2F3%29i Now combine like terms.


So %281%2F6-i%29%5E2 FOILs to -35%2F36-%281%2F3%29i.


In other words, %281%2F6-i%29%5E2=-35%2F36-%281%2F3%29i.


Complex_Numbers/195738: Divide: (6 + 3i)/6 – 3i)
1 solutions

Answer 146786 by jim_thompson5910(28504) About Me  on 2009-05-10 22:52:16 (Show Source):
You can put this solution on YOUR website!

%286%2B3i%29%2F%286-3i%29 Start with the given expression.


%28%286%2B3i%29%2F%286-3i%29%29%28%286%2B3i%29%2F%286%2B3i%29%29 Multiply the fraction by %286%2B3i%29%2F%286%2B3i%29.


%28%286%2B3i%29%286%2B3i%29%29%2F%28%286-3i%29%286%2B3i%29%29 Combine the fractions.


FOIL the numerator.


FOIL the denominator.


%2836%2B18i%2B18i%2B9i%5E2%29%2F%2836%2B18i-18i-9i%5E2%29 Multiply.


%2827%2B36i%29%2F%2845%29 Combine like terms.


%2827%29%2F%2845%29%2B%28%2836%29%2F%2845%29%29i Break up the fraction.


3%2F5%2B%284%2F5%29i Reduce.


So %286%2B3i%29%2F%286-3i%29=3%2F5%2B%284%2F5%29i.


So the expression is now in standard form a%2Bbi where a=3%2F5 and b=4%2F5


Polynomials-and-rational-expressions/195739: what is 4s+s-4 + 3s-5s + 2 equals
1 solutions

Answer 146785 by jim_thompson5910(28504) About Me  on 2009-05-10 22:50:57 (Show Source):
You can put this solution on YOUR website!
4s%2Bs-4%2B3s-5s%2B2 Start with the given expression


%284s%2Bs%2B3s-5s%29%2B%28-4%2B2%29 Group like terms


3s-2 Combine like terms


So 4s%2Bs-4%2B3s-5s%2B2=3s-2


Quadratic_Equations/195740: Solve by factoring: 25x^2 + 2x + 1 = 12x
1 solutions

Answer 146784 by jim_thompson5910(28504) About Me  on 2009-05-10 22:49:52 (Show Source):
You can put this solution on YOUR website!
25x%5E2%2B2x%2B1=12x Start with the given equation.


25x%5E2%2B2x%2B1-12x=0 Subtract 12x from both sides.


25x%5E2-10x%2B1=0 Combine like terms.


%285x-1%29%5E2=0 Factor


5x-1=0 Take the square root of both sides


5x=0%2B1 Add 1 to both sides.


5x=1 Combine like terms on the right side.


x=%281%29%2F%285%29 Divide both sides by 5 to isolate x.


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

Answer:

So the answer is x=1%2F5 which in decimal form is x=0.2.


Exponential-and-logarithmic-functions/195736: These are problemsusing expotential equations. Any help you could offer would be greatly appreciated because I am struggling with these. Thank you.
1. The volume of a cubical bin is 27 cubic feet. What are the length, width, and height?
2. The formual for nth term b of a geo series is b=ar to the n-1
Find n when b=1024 a=16 4-2
3. If a set has three elements, how many subsets does it have?
1 solutions

Answer 146783 by jim_thompson5910(28504) About Me  on 2009-05-10 22:47:20 (Show Source):
You can put this solution on YOUR website!
1)

The volume of a cube is simply equal to the side length cubed. So take the cube root of 27 to get 3. So the width, length, and height are 3 feet.


Note: all sides of a cube are equal.


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

2)

I'm not sure what you mean by a=16 4-2 ???

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

3)

To find the number of subsets of any set, simply raise the number of elements of that set as a power of 2 like so:

2%5E3=8


So there are 8 subsets


Proof:

Here are the 8 subsets of set {a,b,c}


{a,b,c},
{a,b}, {a,c}, {b,c}
{a}, {b}, {c}
{}


Polynomials-and-rational-expressions/195735: what is 3c+4 + 5c+2 equal
1 solutions

Answer 146782 by jim_thompson5910(28504) About Me  on 2009-05-10 22:23:18 (Show Source):
You can put this solution on YOUR website!
3c%2B4%2B5c%2B2 Start with the given expression


%283c%2B5c%29%2B%284%2B2%29 Group like terms


8c%2B6 Combine like terms


So 3c%2B4%2B5c%2B2=8c%2B6


Miscellaneous_Word_Problems/195733: Building a pool in the shape of an ellipse. The equation for the pool is x^2/324 + y^2/196 = 1 Find the longest distance and shortest distance across the pool.
I'm not sure where to start?
y^2=1-x^2/324 and then square both sides?
1 solutions

Answer 146778 by jim_thompson5910(28504) About Me  on 2009-05-10 21:56:03 (Show Source):
You can put this solution on YOUR website!
x%5E2%2F324+%2B+y%5E2%2F196+=+1+ Start with the given equation.


x%5E2%2F18%5E2+%2B+y%5E2%2F196+=+1+ Rewrite 324 as 18%5E2


x%5E2%2F18%5E2+%2B+y%5E2%2F14%5E2+=+1+ Rewrite 196 as 14%5E2


So the equation is now in the form %28x-h%29%5E2%2Fa%5E2%2B%28y-k%29%5E2%2Fb%5E2=1 (which is the general equation of an ellipse) where h=0, k=0, a=18 and b=14


The longest distance between any two points along a line on the ellipse falls on the major axis. The length of the semi major axis simply turns out to be the larger value of "a" or "b"

Since "a" is larger, this means that the length of the semi major axis is 18 units. Double this value to get 36 units.

So the the longest distance across the pool is 36 units.


For the shortest distance, just use the smaller value 14 and double it to 28.


So the the shortest distance across the pool is 28 units.


Polynomials-and-rational-expressions/195729: factor the trinomial
a^2+10a+21
1 solutions

Answer 146772 by jim_thompson5910(28504) About Me  on 2009-05-10 21:39:29 (Show Source):
You can put this solution on YOUR website!

Looking at the expression a%5E2%2B10a%2B21, we can see that the first coefficient is 1, the second coefficient is 10, and the last term is 21.


Now multiply the first coefficient 1 by the last term 21 to get %281%29%2821%29=21.


Now the question is: what two whole numbers multiply to 21 (the previous product) and add to the second coefficient 10?


To find these two numbers, we need to list all of the factors of 21 (the previous product).


Factors of 21:
1,3,7,21
-1,-3,-7,-21


Note: list the negative of each factor. This will allow us to find all possible combinations.


These factors pair up and multiply to 21.
1*21
3*7
(-1)*(-21)
(-3)*(-7)

Now let's add up each pair of factors to see if one pair adds to the middle coefficient 10:


First NumberSecond NumberSum
1211+21=22
373+7=10
-1-21-1+(-21)=-22
-3-7-3+(-7)=-10



From the table, we can see that the two numbers 3 and 7 add to 10 (the middle coefficient).


So the two numbers 3 and 7 both multiply to 21 and add to 10


Now replace the middle term 10a with 3a%2B7a. Remember, 3 and 7 add to 10. So this shows us that 3a%2B7a=10a.


a%5E2%2Bhighlight%283a%2B7a%29%2B21 Replace the second term 10a with 3a%2B7a.


%28a%5E2%2B3a%29%2B%287a%2B21%29 Group the terms into two pairs.


a%28a%2B3%29%2B%287a%2B21%29 Factor out the GCF a from the first group.


a%28a%2B3%29%2B7%28a%2B3%29 Factor out 7 from the second group. The goal of this step is to make the terms in the second parenthesis equal to the terms in the first parenthesis.


%28a%2B7%29%28a%2B3%29 Combine like terms. Or factor out the common term a%2B3

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


Answer:


So a%5E2%2B10a%2B21 factors to %28a%2B7%29%28a%2B3%29.


Polynomials-and-rational-expressions/195730: factor by grouping
7x^3-7x^2-x+1

1 solutions

Answer 146771 by jim_thompson5910(28504) About Me  on 2009-05-10 21:38:56 (Show Source):
You can put this solution on YOUR website!
7x%5E3-7x%5E2-x%2B1 Start with the given expression


%287x%5E3-7x%5E2%29%2B%28-x%2B1%29 Group like terms


7x%5E2%28x-1%29-1%28x-1%29 Factor out the GCF 7x%5E2 out of the first group. Factor out the GCF -1 out of the second group


%287x%5E2-1%29%28x-1%29 Since we have the common term x-1, we can combine like terms


So 7x%5E3-7x%5E2-x%2B1 factors to %287x%5E2-1%29%28x-1%29


Polynomials-and-rational-expressions/195731: multiply and simplify
(6t)*2(6t)*4
1 solutions

Answer 146770 by jim_thompson5910(28504) About Me  on 2009-05-10 21:37:59 (Show Source):


Polynomials-and-rational-expressions/195713: Hello,
Not sure if I chose the right catorgory but I need help with the following problem.
The area of a rectangle is 55 square meters. Find the length and width of the rectangle if its length is 6 meters greater than its width. Use an equation and the formula for area of a rectangle A = l × w
Thank you!
1 solutions

Answer 146769 by jim_thompson5910(28504) About Me  on 2009-05-10 21:36:16 (Show Source):
You can put this solution on YOUR website!
First, we'll use the area of a rectangle formula A=LW. Also, since "its length is 6 meters greater than its width", this means that L=W%2B6


A=LW Start with the given equation.


55=%28W%2B6%29W Plug in L=W%2B6


55=W%28W%2B6%29 Rearrange the terms.


55=W%5E2%2B6W Distribute


0=W%5E2%2B6W-55 Subtract 55 from both sides.


Notice we have a quadratic equation in the form of 0=aW%5E2%2BbW%2Bc where a=1, b=6, and c=-55


Let's use the quadratic formula to solve for W


W+=+%28-b+%2B-+sqrt%28+b%5E2-4ac+%29%29%2F%282a%29 Start with the quadratic formula


W+=+%28-%286%29+%2B-+sqrt%28+%286%29%5E2-4%281%29%28-55%29+%29%29%2F%282%281%29%29 Plug in a=1, b=6, and c=-55


W+=+%28-6+%2B-+sqrt%28+36-4%281%29%28-55%29+%29%29%2F%282%281%29%29 Square 6 to get 36.


W+=+%28-6+%2B-+sqrt%28+36--220+%29%29%2F%282%281%29%29 Multiply 4%281%29%28-55%29 to get -220


W+=+%28-6+%2B-+sqrt%28+36%2B220+%29%29%2F%282%281%29%29 Rewrite sqrt%2836--220%29 as sqrt%2836%2B220%29


W+=+%28-6+%2B-+sqrt%28+256+%29%29%2F%282%281%29%29 Add 36 to 220 to get 256


W+=+%28-6+%2B-+sqrt%28+256+%29%29%2F%282%29 Multiply 2 and 1 to get 2.


W+=+%28-6+%2B-+16%29%2F%282%29 Take the square root of 256 to get 16.


W+=+%28-6+%2B+16%29%2F%282%29 or W+=+%28-6+-+16%29%2F%282%29 Break up the expression.


W+=+%2810%29%2F%282%29 or W+=++%28-22%29%2F%282%29 Combine like terms.


W+=+5 or W+=+-11 Simplify.


So the possible answers are W+=+5 or W+=+-11


However, a negative width doesn't make much sense. So this means we'll ignore W+=+-11


So the solution is W+=+5 which makes the width 5 meters.


L=W%2B6 Go back to the second equation


L=5%2B6 Plug in z+=+5


L=11 Add


So the length is 11 meters.


Equations/195714: I need to solve this, but no idea how, help please is homework for tomorrow
3 (-4b) -2 (a-b-c)=
1 solutions

Answer 146767 by jim_thompson5910(28504) About Me  on 2009-05-10 21:29:55 (Show Source):
You can put this solution on YOUR website!
3%28-4b%29-2%28a-b-c%29 Start with the given expression.


3%28-4b%29-2%28a%29-2%28-b%29-2%28-c%29 Distribute


-12b-2a%2B2b%2B2c Multiply


-2a-10b%2B2c Combine like terms.


So 3%28-4b%29-2%28a-b-c%29=-2a-10b%2B2c


Polynomials-and-rational-expressions/195727: divide & check
48x*3y*2
----------------
8x*7y*2
1 solutions

Answer 146766 by jim_thompson5910(28504) About Me  on 2009-05-10 21:28:13 (Show Source):
You can put this solution on YOUR website!

%2848x%5E3y%5E2%29%2F%288x%5E7y%5E2%29 Start with the given expression.


Expand.


Note: 48x%5E3y%5E2=2%2A2%2A2%2A2%2A3%2Ax%2Ax%2Ax%2Ay%2Ay and 8x%5E7y%5E2=2%2A2%2A2%2Ax%2Ax%2Ax%2Ax%2Ax%2Ax%2Ax%2Ay%2Ay


Highlight the common terms.


Cancel out the common terms.


%282%2A3%29%2F%28x%2Ax%2Ax%2Ax%29 Simplify.


6%2F%28x%5E4%29 Multiply.


So %2848x%5E3y%5E2%29%2F%288x%5E7y%5E2%29 simplifies to 6%2F%28x%5E4%29.


In other words, %2848x%5E3y%5E2%29%2F%288x%5E7y%5E2%29=6%2F%28x%5E4%29 where every variable is non zero


Polynomials-and-rational-expressions/195726: divide & check
56x*7-64x*6+56x*4
-------------------
8x*4
1 solutions

Answer 146765 by jim_thompson5910(28504) About Me  on 2009-05-10 21:25:31 (Show Source):
You can put this solution on YOUR website!
Note: use ^ for exponent instead of *


%2856x%5E7-64x%5E6%2B56x%5E4%29%2F%288x%5E4%29 Start with the given expression.


%288x%5E4%287x%5E3-8x%5E2%2B7%29%29%2F%288x%5E4%29 Factor out the GCF 8x%5E4 from the numerator


%28highlight%288x%5E4%29%287x%5E3-8x%5E2%2B7%29%29%2Fhighlight%288x%5E4%29 Highlight the common terms.


%28cross%288x%5E4%29%287x%5E3-8x%5E2%2B7%29%29%2Fcross%288x%5E4%29 Cancel out the common terms.


7x%5E3-8x%5E2%2B7 Simplify


So %2856x%5E7-64x%5E6%2B56x%5E4%29%2F%288x%5E4%29=7x%5E3-8x%5E2%2B7 where x%3C%3E0



Note: you can use a graph to verify your answer.


Polynomials-and-rational-expressions/195725: factor complety
5a*2-26a+5
1 solutions

Answer 146764 by jim_thompson5910(28504) About Me  on 2009-05-10 21:22:17 (Show Source):
You can put this solution on YOUR website!
Note: use ^ for exponent instead of *




Looking at the expression 5a%5E2-26a%2B5, we can see that the first coefficient is 5, the second coefficient is -26, and the last term is 5.


Now multiply the first coefficient 5 by the last term 5 to get %285%29%285%29=25.


Now the question is: what two whole numbers multiply to 25 (the previous product) and add to the second coefficient -26?


To find these two numbers, we need to list all of the factors of 25 (the previous product).


Factors of 25:
1,5,25
-1,-5,-25


Note: list the negative of each factor. This will allow us to find all possible combinations.


These factors pair up and multiply to 25.
1*25
5*5
(-1)*(-25)
(-5)*(-5)

Now let's add up each pair of factors to see if one pair adds to the middle coefficient -26:


First NumberSecond NumberSum
1251+25=26
555+5=10
-1-25-1+(-25)=-26
-5-5-5+(-5)=-10



From the table, we can see that the two numbers -1 and -25 add to -26 (the middle coefficient).


So the two numbers -1 and -25 both multiply to 25 and add to -26


Now replace the middle term -26a with -a-25a. Remember, -1 and -25 add to -26. So this shows us that -a-25a=-26a.


5a%5E2%2Bhighlight%28-a-25a%29%2B5 Replace the second term -26a with -a-25a.


%285a%5E2-a%29%2B%28-25a%2B5%29 Group the terms into two pairs.


a%285a-1%29%2B%28-25a%2B5%29 Factor out the GCF a from the first group.


a%285a-1%29-5%285a-1%29 Factor out 5 from the second group. The goal of this step is to make the terms in the second parenthesis equal to the terms in the first parenthesis.


%28a-5%29%285a-1%29 Combine like terms. Or factor out the common term 5a-1

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


Answer:


So 5a%5E2-26a%2B5 factors to %28a-5%29%285a-1%29.


Polynomials-and-rational-expressions/195720: subtract
(xy-ab-8)-(xy-3ab-1)
1 solutions

Answer 146763 by jim_thompson5910(28504) About Me  on 2009-05-10 21:20:50 (Show Source):
You can put this solution on YOUR website!
%28xy-ab-8%29-%28xy-3ab-1%29 Start with the given expression.


xy-ab-8-xy%2B3ab%2B1 Distribute


%28xy-xy%29%2B%28-ab%2B3ab%29%2B%28-8%2B1%29 Group like terms.


0xy%2B2ab-7 Combine like terms.


2ab-7 Simplify.


So %28xy-ab-8%29-%28xy-3ab-1%29=2ab-7


Quadratic_Equations/195697: 7x^2-16x-28=0
11x^2=8
1 solutions

Answer 146762 by jim_thompson5910(28504) About Me  on 2009-05-10 21:18:41 (Show Source):
You can put this solution on YOUR website!
# 1


7x%5E2-16x-28=0 Start with the given equation.


Notice we have a quadratic equation in the form of ax%5E2%2Bbx%2Bc where a=7, b=-16, and c=-28


Let's use the quadratic formula to solve for x


x+=+%28-b+%2B-+sqrt%28+b%5E2-4ac+%29%29%2F%282a%29 Start with the quadratic formula


x+=+%28-%28-16%29+%2B-+sqrt%28+%28-16%29%5E2-4%287%29%28-28%29+%29%29%2F%282%287%29%29 Plug in a=7, b=-16, and c=-28


x+=+%2816+%2B-+sqrt%28+%28-16%29%5E2-4%287%29%28-28%29+%29%29%2F%282%287%29%29 Negate -16 to get 16.


x+=+%2816+%2B-+sqrt%28+256-4%287%29%28-28%29+%29%29%2F%282%287%29%29 Square -16 to get 256.


x+=+%2816+%2B-+sqrt%28+256--784+%29%29%2F%282%287%29%29 Multiply 4%287%29%28-28%29 to get -784


x+=+%2816+%2B-+sqrt%28+256%2B784+%29%29%2F%282%287%29%29 Rewrite sqrt%28256--784%29 as sqrt%28256%2B784%29


x+=+%2816+%2B-+sqrt%28+1040+%29%29%2F%282%287%29%29 Add 256 to 784 to get 1040


x+=+%2816+%2B-+sqrt%28+1040+%29%29%2F%2814%29 Multiply 2 and 7 to get 14.


x+=+%2816+%2B-+4%2Asqrt%2865%29%29%2F%2814%29 Simplify the square root (note: If you need help with simplifying square roots, check out this solver)


x+=+%2816%2B4%2Asqrt%2865%29%29%2F%2814%29 or x+=+%2816-4%2Asqrt%2865%29%29%2F%2814%29 Break up the expression.


x+=+%288%2B2%2Asqrt%2865%29%29%2F%287%29 or x+=+%288-2%2Asqrt%2865%29%29%2F%287%29 Reduce


So the answers are x+=+%288%2B2%2Asqrt%2865%29%29%2F%287%29 or x+=+%288-2%2Asqrt%2865%29%29%2F%287%29


which approximate to x=3.446 or x=-1.161






# 2




11x%5E2=8 Start with the given equation.


x%5E2=8%2F11 Divide both sides by 11.


x=%27%27%2B-sqrt%288%2F11%29 Take the square root of both sides.


x=sqrt%288%2F11%29 or x=-sqrt%288%2F11%29 Break up the "plus/minus" to form two equations.


x=%282%2Asqrt%2822%29%29%2F11 or x=-%282%2Asqrt%2822%29%29%2F11 Simplify the square root.


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


Answer:


So the solutions are x=%282%2Asqrt%2822%29%29%2F11 or x=-%282%2Asqrt%2822%29%29%2F11.


Polynomials-and-rational-expressions/195721: multiply
(x5+7x)(x5-7x)
1 solutions

Answer 146761 by jim_thompson5910(28504) About Me  on 2009-05-10 21:14:27 (Show Source):
You can put this solution on YOUR website!
%28x%5E5%2B7x%29%28x%5E5-7x%29 Start with the given expression.


Now let's FOIL the expression.


Remember, when you FOIL an expression, you follow this procedure:


%28highlight%28x%5E5%29%2B7x%29%28highlight%28x%5E5%29-7x%29 Multiply the First terms:%28x%5E5%29%2A%28x%5E5%29=x%5E10.


%28highlight%28x%5E5%29%2B7x%29%28x%5E5%2Bhighlight%28-7x%29%29 Multiply the Outer terms:%28x%5E5%29%2A%28-7%2Ax%29=-7%2Ax%5E6.


%28x%5E5%2Bhighlight%287x%29%29%28highlight%28x%5E5%29-7x%29 Multiply the Inner terms:%287%2Ax%29%2A%28x%5E5%29=7%2Ax%5E6.


%28x%5E5%2Bhighlight%287x%29%29%28x%5E5%2Bhighlight%28-7x%29%29 Multiply the Last terms:%287%2Ax%29%2A%28-7%2Ax%29=-49%2Ax%5E2.


---------------------------------------------------
So we have the terms: x%5E10, -7%2Ax%5E6, 7%2Ax%5E6, and -49%2Ax%5E2


x%5E10-7%2Ax%5E6%2B7%2Ax%5E6-49%2Ax%5E2 Now add every term listed above to make a single expression.


x%5E10-49%2Ax%5E2 Now combine like terms.


So %28x%5E5%2B7x%29%28x%5E5-7x%29 FOILs to x%5E10-49%2Ax%5E2.


In other words, %28x%5E5%2B7x%29%28x%5E5-7x%29=x%5E10-49%2Ax%5E2.


Polynomials-and-rational-expressions/195719: solve
b2-7b+12=0
1 solutions

Answer 146760 by jim_thompson5910(28504) About Me  on 2009-05-10 21:13:33 (Show Source):
You can put this solution on YOUR website!
b%5E2-7b%2B12=0 Start with the given equation.


Notice we have a quadratic equation in the form of Ab%5E2%2BBb%2BC where A=1, B=-7, and C=12


Let's use the quadratic formula to solve for b


b+=+%28-B+%2B-+sqrt%28+B%5E2-4AC+%29%29%2F%282A%29 Start with the quadratic formula


b+=+%28-%28-7%29+%2B-+sqrt%28+%28-7%29%5E2-4%281%29%2812%29+%29%29%2F%282%281%29%29 Plug in A=1, B=-7, and C=12


b+=+%287+%2B-+sqrt%28+%28-7%29%5E2-4%281%29%2812%29+%29%29%2F%282%281%29%29 Negate -7 to get 7.


b+=+%287+%2B-+sqrt%28+49-4%281%29%2812%29+%29%29%2F%282%281%29%29 Square -7 to get 49.


b+=+%287+%2B-+sqrt%28+49-48+%29%29%2F%282%281%29%29 Multiply 4%281%29%2812%29 to get 48


b+=+%287+%2B-+sqrt%28+1+%29%29%2F%282%281%29%29 Subtract 48 from 49 to get 1


b+=+%287+%2B-+sqrt%28+1+%29%29%2F%282%29 Multiply 2 and 1 to get 2.


b+=+%287+%2B-+1%29%2F%282%29 Take the square root of 1 to get 1.


b+=+%287+%2B+1%29%2F%282%29 or b+=+%287+-+1%29%2F%282%29 Break up the expression.


b+=+%288%29%2F%282%29 or b+=++%286%29%2F%282%29 Combine like terms.


b+=+4 or b+=+3 Simplify.


So the answers are b+=+4 or b+=+3


Rational-functions/195715: I hope i picked the right section to put this problem in.
alright here is the problem, i am totally lost on how to do this:
(x/x+4) - (2/x-1) = (20/x^2+3x-4)
HELP!
1 solutions

Answer 146759 by jim_thompson5910(28504) About Me  on 2009-05-10 21:11:57 (Show Source):
You can put this solution on YOUR website!
x%2F%28x%2B4%29-2%2F%28x-1%29=20%2F%28x%5E2%2B3x-4%29 Start with the given equation.


x%2F%28x%2B4%29-2%2F%28x-1%29=20%2F%28%28x%2B4%29%28x-1%29%29 Factor. Take note that x%3C%3E-4 or x%3C%3E1 as these values cause a division by zero.


Multiply every term on both sides by the LCD %28x%2B4%29%28x-1%29. Doing this will eliminate all of the fractions.


%28x-1%29%28x%29-%28x%2B4%29%282%29=20 Cancel out and simplify


x%28x-1%29-2%28x%2B4%29=20 Rearrange the terms.


x%5E2-x-2x-8=20 Distribute.


x%5E2-x-2x-8-20=0 Subtract 20 from both sides.


x%5E2-3x-28=0 Combine like terms.


Notice we have a quadratic equation in the form of ax%5E2%2Bbx%2Bc where a=1, b=-3, and c=-28


Let's use the quadratic formula to solve for x


x+=+%28-b+%2B-+sqrt%28+b%5E2-4ac+%29%29%2F%282a%29 Start with the quadratic formula


x+=+%28-%28-3%29+%2B-+sqrt%28+%28-3%29%5E2-4%281%29%28-28%29+%29%29%2F%282%281%29%29 Plug in a=1, b=-3, and c=-28


x+=+%283+%2B-+sqrt%28+%28-3%29%5E2-4%281%29%28-28%29+%29%29%2F%282%281%29%29 Negate -3 to get 3.


x+=+%283+%2B-+sqrt%28+9-4%281%29%28-28%29+%29%29%2F%282%281%29%29 Square -3 to get 9.


x+=+%283+%2B-+sqrt%28+9--112+%29%29%2F%282%281%29%29 Multiply 4%281%29%28-28%29 to get -112


x+=+%283+%2B-+sqrt%28+9%2B112+%29%29%2F%282%281%29%29 Rewrite sqrt%289--112%29 as sqrt%289%2B112%29


x+=+%283+%2B-+sqrt%28+121+%29%29%2F%282%281%29%29 Add 9 to 112 to get 121


x+=+%283+%2B-+sqrt%28+121+%29%29%2F%282%29 Multiply 2 and 1 to get 2.


x+=+%283+%2B-+11%29%2F%282%29 Take the square root of 121 to get 11.


x+=+%283+%2B+11%29%2F%282%29 or x+=+%283+-+11%29%2F%282%29 Break up the expression.


x+=+%2814%29%2F%282%29 or x+=++%28-8%29%2F%282%29 Combine like terms.


x+=+7 or x+=+-4 Simplify.


So the possible answers are x+=+7 or x+=+-4


However, we stated earlier that x%3C%3E-4 or x%3C%3E1 (they cause a division by zero). So we must ignore the possible solution x+=+-4 (it is not in the domain)


============================================================

Answer:


So the only solution is x+=+7


Square-cubic-other-roots/195716: Simplify square roots: i.e. Simplify the square root of 36x^4y^5 or square root of 121x^5 divided by 9
1 solutions

Answer 146756 by jim_thompson5910(28504) About Me  on 2009-05-10 21:05:18 (Show Source):
You can put this solution on YOUR website!
# 1



sqrt%2836%2Ax%5E4%2Ay%5E5%29 Start with the given expression.


sqrt%2836%2Ax%5E2%2Ax%5E2%2Ay%5E5%29 Factor x%5E4 into x%5E2%2Ax%5E2


sqrt%2836%2Ax%5E2%2Ax%5E2%2Ay%5E2%2Ay%5E2%2Ay%29 Factor y%5E5 into y%5E2%2Ay%5E2%2Ay


Break up the square root using the identity sqrt%28A%2AB%29=sqrt%28A%29%2Asqrt%28B%29.


6%2Asqrt%28x%5E2%29%2Asqrt%28x%5E2%29%2Asqrt%28y%5E2%29%2Asqrt%28y%5E2%29%2Asqrt%28y%29 Take the square root of 36 to get 6.


6%2Ax%2Ax%2Asqrt%28y%5E2%29%2Asqrt%28y%5E2%29%2Asqrt%28y%29 Take the square root of x%5E2 to get x.


6%2Ax%2Ax%2Ay%2Ay%2Asqrt%28y%29 Take the square root of y%5E2 to get y.


6x%5E2y%5E2%2Asqrt%28y%29 Multiply.

==================================================

Answer:


So sqrt%2836%2Ax%5E4%2Ay%5E5%29 simplifies to 6x%5E2y%5E2%2Asqrt%28y%29


In other words, sqrt%2836%2Ax%5E4%2Ay%5E5%29=6x%5E2y%5E2%2Asqrt%28y%29 where every variable is non-negative.





# 2


sqrt%28%28121x%5E5%29%2F9%29 Start with the given expression.


%28sqrt%28121x%5E5%29%29%2Fsqrt%289%29 Break up the root.


%28sqrt%28121x%5E5%29%29%2F3 Take the square root of 9 to get 3.


sqrt%28121%2Ax%5E2%2Ax%5E2%2Ax%29%2F3 Factor x%5E5 into x%5E2%2Ax%5E2%2Ax


%28sqrt%28121%29%2Asqrt%28x%5E2%29%2Asqrt%28x%5E2%29%2Asqrt%28x%29%29%2F3 Break up the square root using the identity sqrt%28A%2AB%29=sqrt%28A%29%2Asqrt%28B%29.


%2811%2Asqrt%28x%5E2%29%2Asqrt%28x%5E2%29%2Asqrt%28x%29%29%2F3 Take the square root of 121 to get 11.


%2811%2Ax%2Ax%2Asqrt%28x%29%29%2F3 Take the square root of x%5E2 to get x.


%2811%2F3%29x%5E2%2Asqrt%28x%29 Rearrange and multiply the terms.

==================================================

Answer:


So sqrt%28%28121x%5E5%29%2F9%29 simplifies to %2811%2F3%29x%5E2%2Asqrt%28x%29


In other words, sqrt%28%28121x%5E5%29%2F9%29=%2811%2F3%29x%5E2%2Asqrt%28x%29 where x%3E=0


Travel_Word_Problems/195718: A baseball player has hit a ball. The height, y, of the ball x seconds after it is hit is given by y= -16x^2 + 80x + 3.
At what time will the ball reach its maximum height? I used the quadratic formula and my answer was 2.04
What is the maximum height of the ball? I used the original formula.My answer was 232.78
When will the ball hit the ground? My answer was 4.08
Is this right??
thanks
1 solutions

Answer 146754 by jim_thompson5910(28504) About Me  on 2009-05-10 21:00:16 (Show Source):
You can put this solution on YOUR website!
At what time will the ball reach its maximum height?
What is the maximum height of the ball?

First, we need the vertex. The vertex will tell us what the max height will be:


In order to find the vertex, we first need to find the x-coordinate of the vertex.


To find the x-coordinate of the vertex, use this formula: x=%28-b%29%2F%282a%29.


x=%28-b%29%2F%282a%29 Start with the given formula.


From y=-16x%5E2%2B80x%2B3, we can see that a=-16, b=80, and c=3.


x=%28-%2880%29%29%2F%282%28-16%29%29 Plug in a=-16 and b=80.


x=%28-80%29%2F%28-32%29 Multiply 2 and -16 to get -32.


x=5%2F2 Reduce.


So the x-coordinate of the vertex is x=5%2F2. Note: this means that the axis of symmetry is also x=5%2F2.


Now that we know the x-coordinate of the vertex, we can use it to find the y-coordinate of the vertex.


y=-16x%5E2%2B80x%2B3 Start with the given equation.


y=-16%285%2F2%29%5E2%2B80%285%2F2%29%2B3 Plug in x=5%2F2.


y=-16%2825%2F4%29%2B80%285%2F2%29%2B3 Square 5%2F2 to get 25%2F4.


y=-100%2B80%285%2F2%29%2B3 Multiply -16 and 25%2F4 to get -100.


y=-100%2B200%2B3 Multiply 80 and 5%2F2 to get 200.


y=103 Combine like terms.


So the y-coordinate of the vertex is y=103.


So the vertex is .


which in decimal form is .


So this means that at 2.5 seconds, the ball will be at the max height of 103.






When will the ball hit the ground?


y=+-16x%5E2+%2B+80x+%2B+3 Start with the given equation.


0=+-16x%5E2+%2B+80x+%2B+3 Plug in y=0


Notice we have a quadratic equation in the form of 0=ax%5E2%2Bbx%2Bc where a=-16, b=80, and c=3


Let's use the quadratic formula to solve for x


x+=+%28-b+%2B-+sqrt%28+b%5E2-4ac+%29%29%2F%282a%29 Start with the quadratic formula


x+=+%28-%2880%29+%2B-+sqrt%28+%2880%29%5E2-4%28-16%29%283%29+%29%29%2F%282%28-16%29%29 Plug in a=-16, b=80, and c=3


x+=+%28-80+%2B-+sqrt%28+6400-4%28-16%29%283%29+%29%29%2F%282%28-16%29%29 Square 80 to get 6400.


x+=+%28-80+%2B-+sqrt%28+6400--192+%29%29%2F%282%28-16%29%29 Multiply 4%28-16%29%283%29 to get -192


x+=+%28-80+%2B-+sqrt%28+6400%2B192+%29%29%2F%282%28-16%29%29 Rewrite sqrt%286400--192%29 as sqrt%286400%2B192%29


x+=+%28-80+%2B-+sqrt%28+6592+%29%29%2F%282%28-16%29%29 Add 6400 to 192 to get 6592


x+=+%28-80+%2B-+sqrt%28+6592+%29%29%2F%28-32%29 Multiply 2 and -16 to get -32.


x+=+%28-80+%2B-+8%2Asqrt%28103%29%29%2F%28-32%29 Simplify the square root (note: If you need help with simplifying square roots, check out this solver)


x+=+%28-80%2B8%2Asqrt%28103%29%29%2F%28-32%29 or x+=+%28-80-8%2Asqrt%28103%29%29%2F%28-32%29 Break up the expression.


So the possible answers are x+=+%28-80%2B8%2Asqrt%28103%29%29%2F%28-32%29 or x+=+%28-80-8%2Asqrt%28103%29%29%2F%28-32%29


which approximate to x=-0.037 or x=5.037


Since a negative time doesn't make sense, this means that the only solution is x=5.037


So it will take about 5.037 seconds for the ball to hit the ground.



logarithm/195711: log(small)4(x+3) + log(small)4 (x-3)=2 the fours are small in the bottom corner so that's why i put small.
1 solutions

Answer 146753 by jim_thompson5910(28504) About Me  on 2009-05-10 20:53:36 (Show Source):
You can put this solution on YOUR website!
log%284%2C%28x%2B3%29%29%2Blog%284%2C%28x-3%29%29=2 Start with the given equation.


log%284%2C%28%28x%2B3%29%28x-3%29%29%29=2 Combine the logs using the identity log%28b%2C%28A%29%29%2Blog%28b%2C%28B%29%29=log%28b%2C%28A%2AB%29%29


%28x%2B3%29%28x-3%29=4%5E2 Rewrite the equation using the property: log%28b%2C%28x%29%29=y ====> x=b%5Ey


%28x%2B3%29%28x-3%29=16 Square 4 to get 16


x%5E2-9=16 FOIL


x%5E2=16%2B9 Add 9 to both sides.


x%5E2=25 Combine like terms.


x=%27%27%2B-sqrt%2825%29 Take the square root of both sides.


x=sqrt%2825%29 or x=-sqrt%2825%29 Break up the "plus/minus"


x=5 or x=-5 Take the square root of 25 to get 5



So the possible solutions are x=5 or x=-5



However since you cannot take the log of a negative number, this rules out x=-5 as a solution (since plugging this value in results in a negative argument)

================================================

Answer:

So the only solution is x=5


Quadratic_Equations/195679: A rocket is launched from atop a 101-foot cliff with an initial velocity of 116ft/s.
a. Substitute the values into the vertical motion formula h=-16t^2+vt+c. Let h=0
b.Use the quadratic formula find out how long the rocket will take to hit the ground after it is launched Round to the nearest tenth of a second
1 solutions

Answer 146742 by jim_thompson5910(28504) About Me  on 2009-05-10 15:13:49 (Show Source):
You can put this solution on YOUR website!
a)


h=-16t%5E2%2Bvt%2Bc Start with the given equation.


h=-16t%5E2%2B101t%2B116 Plug in v=101 and c=116


b)

h=-16t%5E2%2B101t%2B116 Start with the given equation.


0=-16t%5E2%2B101t%2B116 Plug in h=0


Notice we have a quadratic equation in the form of 0=at%5E2%2Bbt%2Bc where a=-16, b=101, and c=116


Let's use the quadratic formula to solve for t


t+=+%28-b+%2B-+sqrt%28+b%5E2-4ac+%29%29%2F%282a%29 Start with the quadratic formula


t+=+%28-%28101%29+%2B-+sqrt%28+%28101%29%5E2-4%28-16%29%28116%29+%29%29%2F%282%28-16%29%29 Plug in a=-16, b=101, and c=116


t+=+%28-101+%2B-+sqrt%28+10201-4%28-16%29%28116%29+%29%29%2F%282%28-16%29%29 Square 101 to get 10201.


t+=+%28-101+%2B-+sqrt%28+10201--7424+%29%29%2F%282%28-16%29%29 Multiply 4%28-16%29%28116%29 to get -7424


t+=+%28-101+%2B-+sqrt%28+10201%2B7424+%29%29%2F%282%28-16%29%29 Rewrite sqrt%2810201--7424%29 as sqrt%2810201%2B7424%29


t+=+%28-101+%2B-+sqrt%28+17625+%29%29%2F%282%28-16%29%29 Add 10201 to 7424 to get 17625


t+=+%28-101+%2B-+sqrt%28+17625+%29%29%2F%28-32%29 Multiply 2 and -16 to get -32.


t+=+%28-101+%2B-+5%2Asqrt%28705%29%29%2F%28-32%29 Simplify the square root (note: If you need help with simplifying square roots, check out this solver)


t+=+%28-101%2B5%2Asqrt%28705%29%29%2F%28-32%29 or t+=+%28-101-5%2Asqrt%28705%29%29%2F%28-32%29 Break up the expression.


t+=+%28101-5%2Asqrt%28705%29%29%2F%2832%29 or t+=+%28101%2B5%2Asqrt%28705%29%29%2F%2832%29 Reduce

So the answers are t+=+%28101-5%2Asqrt%28705%29%29%2F%2832%29 or t+=+%28101%2B5%2Asqrt%28705%29%29%2F%2832%29


which approximate to t=-0.992 or t=7.305



Since a negative time doesn't make sense, the only answer is t=7.305


So it takes about 7.305 seconds for the rocket to hit the ground.


Quadratic_Equations/195677: Use the quadratic formula to solve the equation. If necessary, round to the nearest hundredth.
2a^2-46a+252=0
1 solutions

Answer 146740 by jim_thompson5910(28504) About Me  on 2009-05-10 15:02:18 (Show Source):
You can put this solution on YOUR website!
2a%5E2-46a%2B252=0 Start with the given equation.


Notice we have a quadratic equation in the form of Aa%5E2%2BBa%2BC=0 where A=2, B=-46, and C=252


Let's use the quadratic formula to solve for "a"


a+=+%28-B+%2B-+sqrt%28+B%5E2-4AC+%29%29%2F%282A%29 Start with the quadratic formula


a+=+%28-%28-46%29+%2B-+sqrt%28+%28-46%29%5E2-4%282%29%28252%29+%29%29%2F%282%282%29%29 Plug in A=2, B=-46, and C=252


a+=+%2846+%2B-+sqrt%28+%28-46%29%5E2-4%282%29%28252%29+%29%29%2F%282%282%29%29 Negate -46 to get 46.


a+=+%2846+%2B-+sqrt%28+2116-4%282%29%28252%29+%29%29%2F%282%282%29%29 Square -46 to get 2116.


a+=+%2846+%2B-+sqrt%28+2116-2016+%29%29%2F%282%282%29%29 Multiply 4%282%29%28252%29 to get 2016


a+=+%2846+%2B-+sqrt%28+100+%29%29%2F%282%282%29%29 Subtract 2016 from 2116 to get 100


a+=+%2846+%2B-+sqrt%28+100+%29%29%2F%284%29 Multiply 2 and 2 to get 4.


a+=+%2846+%2B-+10%29%2F%284%29 Take the square root of 100 to get 10.


a+=+%2846+%2B+10%29%2F%284%29 or a+=+%2846+-+10%29%2F%284%29 Break up the expression.


a+=+%2856%29%2F%284%29 or a+=++%2836%29%2F%284%29 Combine like terms.


a+=+14 or a+=+9 Simplify.


So the solutions are a+=+14 or a+=+9


Linear_Equations_And_Systems_Word_Problems/195674: Hi, I am having a problem with the following question.
On a test containing 120 questions, the final score is based on 1 point for each correct answer and 1/4 of a point subtracted for each incorrect answer. Allan answered all of the questions and received a final score of 100 points. How many questions did Allan answer correctly?
Thank you for your help!
Melissa
1 solutions

Answer 146739 by jim_thompson5910(28504) About Me  on 2009-05-10 14:59:45 (Show Source):
You can put this solution on YOUR website!
Let
x = number of correct answers
y = number of incorrect answers

Since there are 120 questions and you can only get a correct or incorrect answer, this means that x%2By=120

Also, since "the final score is based on 1 point for each correct answer and 1/4 of a point subtracted for each incorrect answer" and Allan "received a final score of 100 points", this means that x-%281%2F4%29%2Ay=100


x%2By=120 Start with the first equation.


y=120-x Subtract x from both sides.


x-%281%2F4%29%2Ay=100 Move onto the second equation


x-%281%2F4%29%2A%28120-x%29=100 Plug in y=120-x


x-%281%2F4%29%2A%28120%29%2B%281%2F4%29x=100 Distribute


x-120%2F4%2B%281%2F4%29x=100 Multiply


x-30%2B%281%2F4%29x=100 Reduce


4%28x%29-4%2830%29%2Bcross%284%29%28%281%2Fcross%284%29%29x%29=4%28100%29 Multiply EVERY term by the LCD 4 to clear any fractions.


4x-120%2Bx=400 Multiply and simplify


5x-120=400 Combine like terms on the left side.


5x=400%2B120 Add 120 to both sides.


5x=520 Combine like terms on the right side.


x=%28520%29%2F%285%29 Divide both sides by 5 to isolate x.


x=104 Reduce.


So this means that Allan answered 104 questions correctly.


Quadratic_Equations/195673: Solve the equation by completing the square. Round to the nearest hundredth if necessary.
3x^2-6x-24=0
1 solutions

Answer 146738 by jim_thompson5910(28504) About Me  on 2009-05-10 14:52:00 (Show Source):
You can put this solution on YOUR website!
3x%5E2-6x-24 Start with the left side of the given equation.


3%28x%5E2-2x-8%29 Factor out the x%5E2 coefficient 3. This step is very important: the x%5E2 coefficient must be equal to 1.


Take half of the x coefficient -2 to get -1. In other words, %281%2F2%29%28-2%29=-1.


Now square -1 to get 1. In other words, %28-1%29%5E2=%28-1%29%28-1%29=1


3%28x%5E2-2x%2Bhighlight%281-1%29-8%29 Now add and subtract 1 inside the parenthesis. Make sure to place this after the "x" term. Notice how 1-1=0. So the expression is not changed.


3%28%28x%5E2-2x%2B1%29-1-8%29 Group the first three terms.


3%28%28x-1%29%5E2-1-8%29 Factor x%5E2-2x%2B1 to get %28x-1%29%5E2.


3%28%28x-1%29%5E2-9%29 Combine like terms.


3%28x-1%29%5E2%2B3%28-9%29 Distribute.


3%28x-1%29%5E2-27 Multiply.


So after completing the square, 3x%5E2-6x-24 transforms to 3%28x-1%29%5E2-27. So 3x%5E2-6x-24=3%28x-1%29%5E2-27.


So 3x%5E2-6x-24=0 is equivalent to 3%28x-1%29%5E2-27=0.


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


Now let's solve 3%28x-1%29%5E2-27=0


3%28x-1%29%5E2-27=0 Start with the given equation.


3%28x-1%29%5E2=0%2B27Add 27 to both sides.


3%28x-1%29%5E2=27 Combine like terms.


%28x-1%29%5E2=%2827%29%2F%283%29 Divide both sides by 3.


%28x-1%29%5E2=9 Reduce.


x-1=0%2B-sqrt%289%29 Take the square root of both sides.


x-1=sqrt%289%29 or x-1=-sqrt%289%29 Break up the "plus/minus" to form two equations.


x-1=3 or x-1=-3 Take the square root of 9 to get 3.


x=1%2B3 or x=1-3 Add 1 to both sides.


x=4 or x=-2 Combine like terms.


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


Answer:


So the solutions are x=4 or x=-2.


Quadratic-relations-and-conic-sections/195669: I have a "conic invasion" worksheet. I have to tell by the equation the type of figure and the specific info needed to graph the equation. PLEASE HELP ME! im not asking for the answers or anything (unless youre feeling generous :) just how to get these started im totally lost.
1.y^2+9(x+13)^2=9
2.x^2+y^2=144 for 10>or=y>or=-12
3.x^2+y^2+10x-10y+46=0
4.y+1=0 for 2>or=x>or=-2
5.2x^2-49y+392=0 for y 6.(y^2)/9 + [(x-13)^2]/1=1
7.3x+2y=4 for 2>or=x>or=0
8.2x^2-49y=294 for y 9.15x+7y=175 for 7>or=x>or=-2
10.5x^2-49y=441 for y 11.15x-7y+175=0 for 0>or=x>or=-2
12.3x-2y+4=0 for 0>or=x>or=-2
13.(x-5)^2+(y-5)^2=4
1 solutions

Answer 146737 by jim_thompson5910(28504) About Me  on 2009-05-10 14:49:19 (Show Source):
You can put this solution on YOUR website!
Method # 1

Simply get each equation into the form Ax%5E2%2BBxy%2BCy%5E2%2BDx%2BEy%2BF=0 and use the following properties:



If B%5E2-4AC%3C0, A=C and B=0, then the equation is a circle


If B%5E2-4AC%3C0 and A%3C%3EC, then the equation is an ellipse


If B%5E2-4AC=0, then the equation is a parabola


If B%5E2-4AC%3E0, then the equation is a hyperbola






Method # 2:

Try to get each equation into one of the following forms:


Circle: %28x-h%29%5E2%2B%28y-k%29%5E2=r%5E2

Ellipse: %28x-h%29%5E2%2Fa%5E2%2B%28y-k%29%5E2%2Fb%5E2=1

Hyperbola: %28x-h%29%5E2%2Fa%5E2-%28y-k%29%5E2%2Fb%5E2=1 (parabolas open in x-direction)

Hyperbola: %28y-k%29%5E2%2Fb%5E2-%28x-h%29%5E2%2Fa%5E2=1 (parabolas open in y-direction)

Parabola (vertex form): y=a%28x-h%29%5E2%2Bk, or

Parabola (vertex form): y=ax%5E2%2Bbx%2Bc (standard form)


Polynomials-and-rational-expressions/195667: Solve (5-x)/(2-x)-(3-2x)/(2x)=1
1 solutions

Answer 146736 by jim_thompson5910(28504) About Me  on 2009-05-10 14:30:36 (Show Source):
You can put this solution on YOUR website!
%285-x%29%2F%282-x%29-%283-2x%29%2F%282x%29=1 Start with the given equation.


Multiply every term on both sides by the LCD 2x%282-x%29. Doing this will eliminate all of the fractions.


2x%285-x%29-%282-x%29%283-2x%29=2x%282-x%29%281%29 Cancel out and simplify


2x%285-x%29-%282-x%29%283-2x%29=2x%282-x%29 Multiply


2x%285-x%29-%286-7x%2B2x%5E2%29=2x%282-x%29 FOIL


10x-2x%5E2-6%2B7x-2x%5E2=4x-2x%5E2 Distribute


10x-2x%5E2-6%2B7x-2x%5E2-4x%2B2x%5E2=0 Get all terms to the left side.


-2x%5E2%2B13x-6=0 Combine like terms.


Notice we have a quadratic equation in the form of ax%5E2%2Bbx%2Bc where a=-2, b=13, and c=-6


Let's use the quadratic formula to solve for x


x+=+%28-b+%2B-+sqrt%28+b%5E2-4ac+%29%29%2F%282a%29 Start with the quadratic formula


x+=+%28-%2813%29+%2B-+sqrt%28+%2813%29%5E2-4%28-2%29%28-6%29+%29%29%2F%282%28-2%29%29 Plug in a=-2, b=13, and c=-6


x+=+%28-13+%2B-+sqrt%28+169-4%28-2%29%28-6%29+%29%29%2F%282%28-2%29%29 Square 13 to get 169.


x+=+%28-13+%2B-+sqrt%28+169-48+%29%29%2F%282%28-2%29%29 Multiply 4%28-2%29%28-6%29 to get 48


x+=+%28-13+%2B-+sqrt%28+121+%29%29%2F%282%28-2%29%29 Subtract 48 from 169 to get 121


x+=+%28-13+%2B-+sqrt%28+121+%29%29%2F%28-4%29 Multiply 2 and -2 to get -4.


x+=+%28-13+%2B-+11%29%2F%28-4%29 Take the square root of 121 to get 11.


x+=+%28-13+%2B+11%29%2F%28-4%29 or x+=+%28-13+-+11%29%2F%28-4%29 Break up the expression.


x+=+%28-2%29%2F%28-4%29 or x+=++%28-24%29%2F%28-4%29 Combine like terms.


x+=+1%2F2 or x+=+6 Simplify.


So the answers are x+=+1%2F2 or x+=+6


Probability-and-statistics/195663: two cards are drawn from a deck of 7 cards numbered 1 through 7. once a card is drawn, it is not replaced. find the probability of drawing a 4 and then a 6.
1 solutions

Answer 146735 by jim_thompson5910(28504) About Me  on 2009-05-10 14:14:58 (Show Source):
You can put this solution on YOUR website!
P(drawing a 4) = 1/7

once a 4 is drawn (and not put back), there are 6 cards left. So

P(drawing a 6 next) = 1/6

So ...

P(drawing a 4 then a 6) = P(drawing a 4) * P(drawing a 6 next) = (1/7)*(1/6) = (1*1)/(7*6) = 1/42


Probability-and-statistics/195661: If a number cube is rolled two times, what is the probability of rolling a 1 both times?
1 solutions

Answer 146733 by jim_thompson5910(28504) About Me  on 2009-05-10 14:07:35 (Show Source):
You can put this solution on YOUR website!
P(rolling 1 twice) = P(rolling a 1 AND rolling a 1) = P(rolling a 1) * P(rolling a 1) = (1/6)*(1/6) = (1*1)/(6*6) = 1/36