How to simplify this .?

(4x^2 - y^2)/(12x^2 - 4xy-y^2)4x2y212x24xyy2

1 Answer
Jul 31, 2017

(4x^2-y^2)/(12x^2-4xy-y^2) = (2x+y)/(6x+y)4x2y212x24xyy2=2x+y6x+y

with exclusion 2x != y2xy

Explanation:

Given:

(4x^2-y^2)/(12x^2-4xy-y^2)4x2y212x24xyy2

We can factor both numerator and denominator and then cancel any common factor.

The numerator is a difference of squares, so factors as:

4x^2-y^2 = (2x)^2-y^2 = (2x-y)(2x+y)4x2y2=(2x)2y2=(2xy)(2x+y)

To factor the denominator find a pair of factors of 1212 which differ by 44. The pair 6, 26,2 works, so use that to split the middle term and factor by grouping:

12x^2-4xy-y^2 = (12x^2-6xy)+(2xy-y^2)12x24xyy2=(12x26xy)+(2xyy2)

color(white)(12x^2-4xy-y^2) = 6x(2x-y)+y(2x-y)12x24xyy2=6x(2xy)+y(2xy)

color(white)(12x^2-4xy-y^2) = (6x+y)(2x-y)12x24xyy2=(6x+y)(2xy)

So we find:

(4x^2-y^2)/(12x^2-4xy-y^2) = (color(red)(cancel(color(black)((2x-y))))(2x+y))/((6x+y)color(red)(cancel(color(black)((2x-y)))))

color(white)((4x^2-y^2)/(12x^2-4xy-y^2)) = (2x+y)/(6x+y)

with exclusion 2x != y