Answer:
A
Step-by-step explanation:
Given (x + h) is a factor of f(x) then f(- h) = 0
Given
p(x) = x³ - 4x² + ax + 20 , with (x + 1) as a factor then
p(- 1) = (- 1)³ - 4(- 1)² - a + 20 = 0 , that is
- 1 - 4 - a + 20 = 0
15 - a = 0 ( subtract 15 from both sides )
- a = - 15 ( multiply both sides by - 1 )
a = 15 , thus
p(x) = x³ - 4x² + 15x + 20
If p(x) is divided by (x + h) then p(- h) is the remainder, so
p(- 2) = (- 2)³ - 4(- 2)² + 15(- 2) + 20 , that is
- 8 - 16 - 30 + 20 = - 34 → A
