Question

Factor the following polynomial completely.

-x² y² + x^4 + 9y² - 9x²

a) (x - 3)(x - 3)(x + y)(x - y)
b) (x + 3)(x + 3)(x + y)(x - y)
c) (x + 3)(x - 3)(x + y)(x - y)

Answer 1

factor by grouping x^2(x^2-y^2)-9(-y^2+x^2)
(x^2-9)(x^2-y^2) differences of squares
(x+3)(x-3)(x-y)(x+y)