Question 317509
(x^2 + 5)(x^2 - 5)

We use FOIL to multiply.

x^4 -5x^2 + 5x^2 - 25

x^4 - 25.

She then needs to replace x with 3 and evaluate the polynomial x^4 - 25.

Let x = 3.

(3)^4 - 25 = 81 - 25 or 56

Done!