Question

How do you factor `81x ^ { 2} - 144`?

Answer 1

The answer is `=9(3x+4)(3x-4)`

Explanation:

We use

`a^2-b^2=(a+b)(a-b)`

Therefore,

`81x^2-144 =9(9x^2-16)`

`=9(3x+4)(3x-4)`