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Recent problems solved by 'vleith'

vleith answered: 1977 problems
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Radicals/241146: I have a question about the powers of "i". I am not understanding the facts about how "i" to the second power = blank or "i" to the 6th powers = blank and so fourth. Can you explain this procedure in detail and explain how it is used in the radical equation?

1 solutions

Answer 176596 by vleith(1977) About Me  on 2009-11-20 14:06:50 (Show Source):
You can put this solution on YOUR website!
i is defined as the
So
i^1 = i
i^2 = -1
i^3 = -i
i^4 = (-1)(-1) = 1
And it repeats in a cycle of 4
i^5 = i^4*i = 1+i = i
i^6 = i^4*i^2 = 1*i^2 = 1 *(-1) = -1
i^7 = i^4*i^3 = 1*i^3 = -i
etc etc
how do you use in a radical? If the value under the radical is negative, then look at that as (-1)*aPositive
for instance = plus or minus 3i


Rational-functions/241144: Find the LCM of x^2 +6x-7 and x^2 +5x - 14
1 solutions

Answer 176595 by vleith(1977) About Me  on 2009-11-20 14:02:14 (Show Source):
You can put this solution on YOUR website!
Don't let the algebra fool you. These LCM problems are done the same way you did them in arithmetic.
1)Find the prime factors in each term
2)Find which prime factor is used more times in each term
3)Collect all of most used prime factors
4)Multiply it all out
=
=
So there are three different prime factors, each used once.
Collect them


Now multiply and simplify and you're done


Equations/241107: Factor completely, if a polynomial is prime state this: thank you
2t^2-7t-4
1 solutions

Answer 176580 by vleith(1977) About Me  on 2009-11-20 11:22:28 (Show Source):
You can put this solution on YOUR website!
This URL can factor
http://72.3.253.76:8080/webMathematica3/quickmath/page.jsp?s1=algebra&s2=factor&s3=basic


Polynomials-and-rational-expressions/241103: please help me with factoring- 16x^4y-y^5
1 solutions

Answer 176578 by vleith(1977) About Me  on 2009-11-20 11:17:52 (Show Source):


Permutations/241099: (n+2)!/n!=56
where n=N
my answer: n= 7

1 solutions

Answer 176577 by vleith(1977) About Me  on 2009-11-20 11:04:35 (Show Source):
You can put this solution on YOUR website!


}



So n = -9 or n=6
Since n=-9 is not possible in n!, then it must be n=6
Which makes sense since n+1=7 and n+2=8 and 7*8 = 56


Equations/241067: How do we solve 2q^3 - 8q^2 - 4950 = 0?
1 solutions

Answer 176540 by vleith(1977) About Me  on 2009-11-20 07:02:03 (Show Source):
You can put this solution on YOUR website!
I don't know any easy way to work this other than 'trying' all the factors.
Divide thru by 2 and then grind out the various factors of 2475.
Or go here and have them give you the answer --> http://www.wolframalpha.com/input/?i=2q^3+-+8q^2+-+4950+%3D+0


Age_Word_Problems/240778: How do I write this problem into an equation:
Alex and Alicia are twins. Kevin is 5 years older than the twins. Their ages total 53. How old are the twins?
1 solutions

Answer 176410 by vleith(1977) About Me  on 2009-11-19 15:47:21 (Show Source):
You can put this solution on YOUR website!
Let the twins age be given by A. You are told Kevin is 5 years older than the twins, so his age is
You are told the three of their ages total 53





So the twins are sweet sixteen and Kevin is 21.
Check your answer is 16+16+21 = 53?


Quadratic_Equations/240789: Hello,
I need some help to:

1. Solve the following equation using quadratic formula
2x^2-3x-1=0
The solution set is? ________

Thanks!!

1 solutions

Answer 176407 by vleith(1977) About Me  on 2009-11-19 15:44:01 (Show Source):
You can put this solution on YOUR website!
use this --. http://www.algebra.com/algebra/homework/quadratic/quadratic.solver


Trigonometry-basics/240803: PLEASE HELP ME SOLVE THIS CIRCULAR FUNCTIONS AND THEIR GRAPHS:
What is the amplitude of y=4 sin 3 x?
1 solutions

Answer 176406 by vleith(1977) About Me  on 2009-11-19 15:43:05 (Show Source):
You can put this solution on YOUR website!
The biggest value any sin can get is 1. So the amplitude is set by the coefficient 4. look at this graph -->
http://www.wolframalpha.com/input/?i=+y%3D4+sin(3x)


Trigonometry-basics/240801: PLEASE HELP ME SOLVE THIS CIRCULAR FUNCTIONS AND THEIR GRAPHS:
A wheel turns 1,500 revolutions per minute.How fast does it turn in radians per second?

1 solutions

Answer 176404 by vleith(1977) About Me  on 2009-11-19 15:41:08 (Show Source):
You can put this solution on YOUR website!
The size of a radian is determined by the requirement that there are radians in a circle. So each revolution is radians
=


radians per second


Quadratic_Equations/240797: I need to a step by step solving this equation:0= x^2+15x-1350 , This is from a word problem using quadratic equation solving cost per person.... I know the answer but I do not know how they got it....help please
1 solutions

Answer 176401 by vleith(1977) About Me  on 2009-11-19 15:34:01 (Show Source):
You can put this solution on YOUR website!
If you 'see' an easy factorization, you can always use that. But for me, once the factors get that large, I prefer the quadratic equation. here is a solver that does it for you --> http://www.algebra.com/algebra/homework/quadratic/quadratic.solver
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation (in our case ) has the following solutons:



For these solutions to exist, the discriminant should not be a negative number.

First, we need to compute the discriminant : .

Discriminant d=5625 is greater than zero. That means that there are two solutions: .




Quadratic expression can be factored:

Again, the answer is: 30, -45. Here's your graph:



Equations/240799: Write the equation of a circle with center at (-5, 2) and radius 5. Please help.
1 solutions

Answer 176400 by vleith(1977) About Me  on 2009-11-19 15:31:04 (Show Source):
You can put this solution on YOUR website!
read this --> http://www.mathwarehouse.com/geometry/circle/equation-of-a-circle.php


Linear-equations/240794: I'm actually in Algebra 1, but we're talking about parallel and prependicular lines. The question says to write an equation in slope-intercept form for each line according to given information.
Contains (3,-5) and is parallel to 5x-2y=10
1 solutions

Answer 176398 by vleith(1977) About Me  on 2009-11-19 15:29:52 (Show Source):
You can put this solution on YOUR website!
Look at this tool --> http://www.algebra.com/algebra/homework/Linear-equations/equation-parallel-or-perpendicular.solver


Linear-systems/240791: How do you write an equation for a line that is parallel to a given line and passes through a given point
(1,3) y=-4x+5
1 solutions

Answer 176397 by vleith(1977) About Me  on 2009-11-19 15:29:18 (Show Source):
You can put this solution on YOUR website!
Look at this solver --> http://www.algebra.com/algebra/homework/Linear-equations/equation-parallel-or-perpendicular.solver


Functions/240795: Find a polynomial function of degree 3 with -2, and 7i as zeros.
1 solutions

Answer 176395 by vleith(1977) About Me  on 2009-11-19 15:26:14 (Show Source):
You can put this solution on YOUR website!
You know that roots result in zeros.
So a zero at x=-2 means (x+2) is a factor in the formula for the polynomial.
Likewise you are told you have an imaginary root at 7i. You know that imaginary roots come in pairs (7i , -7i)
So two more factors are (x-7i) and (x+7i)
Now you have three terms. The polynomial is the product of those three factors.



All you need to do now is simplify by multiplying it all out. I'll leave that to you, because I know you can do that. Ping me if you need more help


Trigonometry-basics/240660: hi,
I am taking a course on N3 maths. Can you help me with the angle of inclination.
The question reads as follows:Determine th slope and angle of inclination of the line passing through points (-2;4) and (4;-1).
To get the andwer calculate m= y2-y1/x2-x1 thus:m=-(5/6)
I know m=tanθ so if the value of m=-5/6 how do i use my calculator to get the degree of the angle? The answer in the book is θ=140.2 degrees?
So how do I get the answer 140.2 degrees????

1 solutions

Answer 176296 by vleith(1977) About Me  on 2009-11-19 06:57:13 (Show Source):
You can put this solution on YOUR website!
Use your calculator and find the "tan-1" button. Mine is the yellow above TAN (TI-83)
Depends on the calc you have, but you need to find the 'arctan' or 'tan -1'.
Tangent takes degrees and turns them into a ratio.
ArcTan takes a ratio (fraction) and turns it into degrees.
When you plug in tan-1(5/6), you'll get 39.8 degrees. Now you need to know which quadrant the plot it in to find 180-39.8


Polynomials-and-rational-expressions/240663: 9/x-4 = 9x+36/?
How will I solve if neither of the numerator or the denominator is missing?
1 solutions

Answer 176295 by vleith(1977) About Me  on 2009-11-19 06:52:24 (Show Source):
You can put this solution on YOUR website!
Let the ? be represented by z. Now solve for z
Use distribution on the left side numerator
divide both sides by 9
multiply both sides by z
isolate z
simplify



Square-cubic-other-roots/240437: Please help me simplify

1 solutions

Answer 176140 by vleith(1977) About Me  on 2009-11-18 16:53:36 (Show Source):
You can put this solution on YOUR website!
thats as simple as it gets.
http://www.wolframalpha.com/input/?i=sqrt(6%2Fx)


Inequalities/240432: i need help solving combined inequalities
like2>x+3>-8
1 solutions

Answer 176139 by vleith(1977) About Me  on 2009-11-18 16:51:53 (Show Source):
You can put this solution on YOUR website!
Solve each part separately first
break it up as
and
now solve each part

-->


Now plot them both and find where they are 'both true"
in this case, you would the numbers that satisfy both equations are



Equations/240430: what do you do if a minus sign is next to a parenthesis?
1 solutions

Answer 176137 by vleith(1977) About Me  on 2009-11-18 16:47:41 (Show Source):
You can put this solution on YOUR website!
Act like it is a "minus 1" and then distribute that across the values inside he parens
For instance
-(2x+3)
-1(2x+3)
-2x -3
get it?


Polygons/240352: a polygon has 32 sides
A) the sum of the measures of the interior angles

1 solutions

Answer 176122 by vleith(1977) About Me  on 2009-11-18 14:15:26 (Show Source):
You can put this solution on YOUR website!
The sum of the measures of the interior angles of a polygon with n sides is (n-2)180
You have 32 sides, so




Numbers_Word_Problems/240351: What is 3 consecutive even numbers that have a sum of 36?
1 solutions

Answer 176121 by vleith(1977) About Me  on 2009-11-18 14:13:31 (Show Source):
You can put this solution on YOUR website!
Let the three numbers be x , x+ 2 and x+4




So the numbers are 10, 12 and 14


Exponents-negative-and-fractional/240353: I need help figuring out how to do this:
-2/7x = 1/5
I am using "/" as the fraction bar
1 solutions

Answer 176120 by vleith(1977) About Me  on 2009-11-18 14:11:24 (Show Source):
You can put this solution on YOUR website!
You want to get x "by itself" on one side of the equal sign

Let's go one small step at a time
1) clear the denominator on the left side.
multiply both sides by 7
divide both sides by -2


Check your answer
Does


Miscellaneous_Word_Problems/240234: Find the number of revolutions made by a circular wheel of area 1.54 m2 in
rolling a distance of 176 m.
1 solutions

Answer 176080 by vleith(1977) About Me  on 2009-11-18 06:09:14 (Show Source):
You can put this solution on YOUR website!
Use the area to rid the radius of the wheel




So the radius is 0.7m
Now use the equation for circumference


meters
How many circumferecnes are in 176m?

Allowing for rounding, I would say 40 revolutions.


Functions/240238: is 8y=7+3x a function
1 solutions

Answer 176078 by vleith(1977) About Me  on 2009-11-18 06:04:12 (Show Source):
You can put this solution on YOUR website!
Yes. that is the equation of a line and the line is not vertical. So every value of x maps to one and only one value for y. Which is the definition of a function.

You can always use the vertical line rule. Plot the given equation. If any vertical line intersects the plot in more than one point, then the equation is NOT a function.

You can plot things at the website -->
http://www.wolframalpha.com/input/?i=8y%3D7%2B3x


expressions/240242: 500=((x)0.12)+x
what is x?
1 solutions

Answer 176077 by vleith(1977) About Me  on 2009-11-18 06:00:43 (Show Source):


Pythagorean-theorem/240244: if the foot of a 13-meter ladder is placed 6 meters from the base of a building, how high up the building will the ladder reach?

1 solutions

Answer 176076 by vleith(1977) About Me  on 2009-11-18 05:59:04 (Show Source):
You can put this solution on YOUR website!
Use Pythagorean theorem.
The 13 meter ladder will be the hypotenuse, one leg is 6 meters. You are asked to find the other leg
Pythagorean theorem




meters


Numbers_Word_Problems/240140: the difference between three times a number and 12 is 12, find the number
1 solutions

Answer 176039 by vleith(1977) About Me  on 2009-11-17 20:31:18 (Show Source):
You can put this solution on YOUR website!
Let x be the number. You are told



Check your answer is 3*8 - 12 = 12??


Graphs/240135: How do you solve the problem: 3x-2y=2
y=2x+8 ?
1 solutions

Answer 176035 by vleith(1977) About Me  on 2009-11-17 20:29:44 (Show Source):
You can put this solution on YOUR website!
Several ways to do this. The sinplest is to plug the value given for y in the second equation, into the first equation and then solving for the remaining variable

plug this value for y into the first equation
simplify and collect terms


Now that you have a value for x, plug that in to either original equation and solve for y




You can also plot the two equation and see where they intersect



Radicals/239927: Solve:
^3√24
^4√48
^3√24 - ^3√375
20^3√-81t^3 - 7^3√24t^3
1 solutions

Answer 175945 by vleith(1977) About Me  on 2009-11-17 14:56:15 (Show Source):
You can put this solution on YOUR website!




Use the same idea for the next one



Same for the next one


3^(1/3)


For the last one





Distributive-associative-commutative-properties/239940: Solve 7x^2=49x
1 solutions

Answer 175942 by vleith(1977) About Me  on 2009-11-17 14:48:43 (Show Source):
You can put this solution on YOUR website!



so either 7x=0 or (x-7)=0
That means x=0 or x = 7