# Thread: Need help factoring this equation using the difference of two squares

1. ## Need help factoring this equation using the difference of two squares

not entirely sure how to do it could someone explain it to me?

(2x + y)^2 - 4

- '^2' being the power of 2 if its unclear :P

2. ## Re: Need help factoring this equation using the difference of two squares

by letting 2x+y = a
then the equation will become
a^2-4
=(a-2)(a+2)
=(2x+y-2)(2x+y+2)

please refer to the identity (a-b)(a+b)=a^2-b^2

3. ## Re: Need help factoring this equation using the difference of two squares

Originally Posted by ryanch94
not entirely sure how to do it could someone explain it to me?

(2x + y)^2 - 4

- '^2' being the power of 2 if its unclear :P
Does it help if you write it as $\displaystyle \displaystyle (2x + y)^2 - 2^2$?

4. ## Re: Need help factoring this equation using the difference of two squares

Originally Posted by piscoau
by letting 2x+y = a
then the equation will become
a^2-4
=(a-2)(a+2)
=(2x+y-2)(2x+y+2)

please refer to the identity (a-b)(a+b)=a^2-b^2
Cheers for that! Seems quite simple now! :L