Question

How to factorise this? (3a)^2 - (12b)^2

Answer 1

`9(a-4b)(a+4b)`

Explanation:

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

So we have:

`(3a-12b)xx(3a+12b)`

`3(a-4b)xx3(a+4b)`

`9(a-4b)(a+4b)`