Answer:
(4x + 7)(x + 10)(x - 10)
Explanation:
4x³ + 7x² - 400x - 700 ( factor the first/second and third/fourth terms )
= x²(4x + 7) - 100(4x + 7) ← factor out (4x + 7) from each term
= (4x + 7)(x² - 100) ← (x² - 100) is a difference of squares and factors as
x² - 100
= x² - 10²
= (x + 10)(x - 10)
then
4x³ + 7x² - 400x - 700 = (4x + 3)(x + 10)(x - 10)