|
Question 990398: How do l solve this fractor 8x2-2xy-y2? Also i need to know how to write the problem into steps.
Answer by Theo(13342)   (Show Source):
You can put this solution on YOUR website! your equation is 8x^2 - 2xy - y^2.
you want to factor it.
treat the x as the variable of interest.
treat the y as a constant.
multiply the coefficient of the x^2 term by the coefficient of the y^2 term to get 8.
the sign is not important right now.
find all the factors of 8.
they are 1 * 8, and 2 * 4.
since your xy term is -2, you are looking for factors that will add up to 2 or subtract down to 2.
the factors of 4 * 2 will do it because 2 - 4 is equal to -2.
your factors will be (4x + y) * (2x - y)
why is this?
mjultiply the factors together and you will see why.
(4x + y) * (2x - y) is equal to 8x^2 - 4xy + 2xy - y^2
combine like terms to get 8x^2 - 2xy - y^2.
since that's your original equation, you have found the right factors.
there are several methods to use in factoring quadratic equations.
the following link outlines some of the most common.
here's a reference that should help.
http://www.purplemath.com/modules/factquad.htm
the key with the one that you are factoring is to treat the y variable as a constant.
if you re-write your equation as:
8x^2 - 2yx - y^2
then 8 is the coefficient of the x^2 term and 2y is the coefficient of the x term and y^2 is the constant term.
treating it as such, you can also factor the equation using the quadratic formula.
good luck.
|
|
|
| |
