9a^4-16a^2?

Question

9a^4-16a^2?

Answer 1

I don't know why this question came to this topic. Anyway, the solution is like this:

9a^4-16a^2

a^2(9a^2-16)

a^2{(3a)^2-(4)^2}

a^2(3a+4)(3a-4) We know that a^2-b^2=(a+b)(a-b)