Question

(x+2)(x-3)(x+5) is identical to x^(3)+ax^(2)-11x+b Find the value of a and the value of b

Answer 1

Answer:

a = 4 and b = - 30

Step-by-step explanation:

Expand the left side and compare like terms on both sides, that is

(x + 2)(x - 3)(x + 5) ← expand the first pair of factors using FOIL

= (x² - x - 6)(x + 5) ← distribute

= x³ + 5x² - x² - 5x - 6x - 30 ← collect like terms

= x³ + 4x² - 11x - 30

Compare like terms with x³ +ax² - 11x + b

4x² and ax² ⇒ a = 4

+ b and - 30 ⇒ b = - 30