Question

Which expression is a factor of 36x2−9?

Answer 1

Answer:

18x - 9

Step-by-step explanation:

Factor the common factor of 9 first which gives $9(4x^{2} -1)$

$4x^{2} - 1$ is the difference of two squares and factors into (2x + 1)(2x - 1)

The complete factorization of $36x^{2} -9$ is 9(2x + 1)(2x - 1).  

So 9(2x - 1) = 18x - 9 is a factor of the original expression.