Question

What is the factorization of the expression below 9x^2-4y^2

A. (3x-2y)(3x-2y)
B. (9x-2y)(x+2y)
C. (3x-2y)(3x+2y)
D. (9x-2y)(x-2y)

Answer 1

Factors 9x^2-4y^2 :

Rewrite 9x^2 as 3x^2 Hint: because 9/3=3

Rewrite 4y^2 as 2y^2 Hint: because 4/2=2

• Remember whatever you do on one side you have to do the other.

Then you say: (3x)^2- (2y)^2

• Since both terms are perfect squares, factor using the difference of squares formula, a^2 - b^2 = (a+b)(a-b) = (3x+2y) (3x−2y)

Multiply 2 by -1 to get:

C. (3x+2y) (3x−2y)

Answer 2

9x^2-4y^2

(3x-2y) (3x+2y)

Choice C