Question

5. If -1,-2 are two zeroes of a polynomial 2x3 + ax2 + bx - 2, then (a, b) = ( ( )​

Answer 1

Step-by-step explanation:

Given -1,-2 are two zeroes of a polynomial 2x^3 + ax^2+ bx - 2

Let f(x) = 2x^3 + ax^2+ bx - 2

f(-1)=0

2(-1)^3 + a(-1)^2+ b(-1) - 2 = 0

-2+a-b-2 =0

a-b =4 ---(1)

f(-2)=0

2(-2)^3 + a(-2)^2+ b(-2) - 2 = 0

-16+4a-2b-2 =0

4a-2b =18

2a-b =9---(2)

(1)-(2) => a-b-2a+b= 4-9

-a= -5

a = 5

substituting a = 5 in equation (1)

5-b = 4

b = 5-4

b = 1

therefore. (a,b) = (5,1)