Question

Factor the polynomial 4x4 – 20x2 – 3x2 + 15 by grouping. What is the resulting expression?

(4x2 + 3)(x2 – 5)
(4x2 – 3)(x2 – 5)
(4x2 – 5)(x2 + 3)
(4x2 + 5)(x2 – 3)

Answer 1

B. (4x2 – 3)(x2 – 5)

Explanation:

Answer 2

4x^4 - 20x^2 - 3x^2 + 15
= (4x^2)(x^2) + (4x^2)(-5) + (-3)(x^2) + (-5)(-3)
= (4x^2)(x^2 - 5) + (-3)(x^2 - 5)
= (4x^2 - 3)(x^2 - 5)

Therefore the answer is (4x^2 - 3)(x^2 - 5)