Question

If -2 and 3 are zeroes of quadratic polynomial xsquare + (a+1)x+b then find the value of and b

Answer 1

Answer:

a = - 2, b = - 6

Step-by-step explanation:

Substitute the values of the zeros into the polynomial and equate to zero.

x² +(a + 1)x + b

x = - 2 → (- 2)² - 2(a + 1) + b = 0 , that is

4 - 2a - 2 + b = 0

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

- 2a + b = - 2 → (1)

x = 3 → 3² + 3(a + 1) + b = 0, that is

9 + 3a + 3 + b = 0

12 + 3a + b = 0 ( subtract 12 from both sides )

3a + b = - 12 → (2)

Subtract (1) from (2) term by term to eliminate b

5a = - 10 ( divide both sides by 5 )

a = - 2

Substitute a = - 2 into either of the 2 equations and evaluate for b

Substituting into (2)

3(- 2) + b = - 12

- 6 + b = - 12 ( add 6 to both sides )

b = - 6

Thus a = - 2 and b = - 6