Question

Factor the expression y4 − 81 using the polynomial identity (x2 − y2) = (x − y)(x + y).

Answer 1

The factored form is (y^2+9)(y^2-9).

Plug the two terms into the equation by finding the root of both.
√y^4= y^2
√81= 9

From here, you plug the terms into the form (x+y)(x-y)
(y^2+9)(y^2-9)

Hope this helps!