Question

Write as a polynomial: (−3xy +a)(3xy +a)

Answer 1

a^2 - 9x^2y^2

Explanation:

(−3xy + a)(3xy + a) =

= (a - 3xy)(a + 3xy)

This is the product of a sum and a difference: (a + b)(a - b) = a^2 - b^2

= a^2 - 9x^2y^2