MCQ
Choose the correct answer from the given four options in the following questions : Given that one of the zeroes of the cubic polynomial $a x^3+b x^2+c x+d$ is zero, the product of the other two zeroes is :
  • A
    $-\frac{\text{c}}{\text{a}}$
  • $\frac{\text{c}}{\text{a}}$
  • C
    $0 $
  • D
    $-\frac{\text{b}}{\text{a}}$

Answer

Correct option: B.
$\frac{\text{c}}{\text{a}}$
Let $p(x)=a x^3+b x^2+c x+d$
Given that, one of the zeroes of the cubic polynomial $p(x)$ is zero,
Let $\alpha,$
$\beta$ and $\gamma$ are the zeroes of cubic polynomial $p(x),$ where $a = 0.$
We know that,
Sum of product of two zeroes at a time $=\frac{\text{c}}{\text{a}}$
$\Rightarrow\ \alpha\beta + \beta\gamma + \gamma\alpha =\frac{\text{c}}{\text{a}}$
$\Rightarrow\ 0\times\beta+\beta\gamma +\gamma\times0=\frac{\text{c}}{\text{a}}\ \big[\because\ \beta = 0,$ given $\big]$
$\Rightarrow\ 0+\beta\gamma + 0 =\frac{\text{c}}{\text{a}}$
$\Rightarrow\ \beta\gamma=\frac{\text{c}}{\text{a}}$
Hence, Product of other two zeroes $=\frac{\text{c}}{\text{a}}.$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free