How do you factor 9y^2 - 1 9y21?

1 Answer
Mar 19, 2018

9y^2-1=(3y+1)(3y-1)9y21=(3y+1)(3y1)

Explanation:

9y^2-19y21
=(3y)^2-(1)^2=(3y)2(1)2
Using the identity a^2-b^2=(a+b)(a-b),a2b2=(a+b)(ab),
You can further simplify ((3y)^2-(1)^2)((3y)2(1)2) as
(3y)^2-(1)^2=(3y+1)(3y-1)(3y)2(1)2=(3y+1)(3y1)