Question

If two zeroes of the polynomial $x^{3}+x^{2}-9x-9$are 3 and -3, then its third zero is
(a) -1
(b) 1
(c) -9
(d) 9

Answer 1

SOLUTION :

The correct option is (a) : - 1 .

Let α = 3 , β = - 3 and γ are the three Zeroes of the cubic  polynomial.

Given :  The cubic  polynomial f(x) = x³ + x² - 9x - 9  

On comparing with  ax³ + bx² + cx + d  

a = 1, b= 1, c = - 9 , d = - 9

Sum of zeroes of cubic  polynomial= −coefficient of x² / coefficient of x³

α + β + γ = −b/a

3  +(-3) +  γ = −1/1

3  - 3 +  γ = − 1

γ = − 1

Hence, the third zero (γ) is − 1 .

HOPE THIS ANSWER WILL HELP YOU..

Answer 2

-1 is correct option