Question

What is the factorization of 49b^ 2 -81 ?

Answer 1

(7b -9)(7b +9)

Explanation:

Each term is a perfect square, so the expression is the difference of squares. In general, that factors as ...

p^2 - q^2 = (p -q)(p +q)

Here, you have p^2 = 49b^2, so p = 7b; and q^2 = 81, so q = 9. Then the factoring is ...

(7b -9)(7b +9)