10th Class Mathematics Polynomials Question Bank MCQs - Polynomials

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

Correct Answer: A

Solution :

[a] Let the third zero of the polynomial \[{{x}^{3}}+{{x}^{2}}-9x-9\] be \[\alpha \].

Now, sum of zeroes \[=\frac{-1}{1}=-1\]

\[\Rightarrow \,\,\,\,\,\,\,\,\,3+(-3)+\alpha =-1\Rightarrow \alpha =-1\]