Question

Please answer this question

Answer 1

Answer:

a = - 2, b = - 1

Step-by-step explanation:

If a polynomial f(x) is divisible by (x + h) then f(- h) = 0

P(x) is divisible by (x + 1), thus P(- 1) = 0 , that is

P(- 1) = (- 1)³ + a(- 1)² - b + 2 = 0 , that is

- 1 + a - b + 2 = 0

a - b + 1 = 0 ( subtract 1 from both sides )

a - b = - 1 → (1)

P(x) is divisible by (x - 2) thus P(2) = 0 , that is

P(2) = 2³ + a(2)² + 2b + 2 = 0 , that is

8 + 4a + 2b + 2 = 0

4a + 2b + 10 = 0 ( subtract 10 from both sides )

4a + 2b = - 10 → (2)

Solve (1) and (2) simultaneously

Multiply (1) by 2

2a - 2b = - 2 → (3)

Add (2) and (3) term by term eliminating the term in b

6a = - 12 ( divide both sides by 6 )

a = - 2

Substitute a = - 2 into (1) and solve for b

- 2 - b = - 1 ( add 2 to both sides )

- b = 1 ( multiply both sides by - 1 )

b = - 1