Choose the correct answer from the given four options in the following questions:
If one of the zeroes of the quadratic polynomial $ (k-1) x^{2}+k x+1 $ is $ -3 $, then the value of $ k $ is
(A) $ \frac{4}{3} $
(B) $ \frac{-4}{3} $
(C) $ \frac{2}{3} $
(D) $ \frac{-2}{3} $

AcademicMathematicsNCERTClass 10

Given: 

One of the zeroes of the quadratic polynomial $( k-1)x^{2}+kx+1$ is $-3$

To do: 

We have o find the value of $k$.

Solution:

One of the zeroes of the quadratic polynomial $( k-1)x^{2}+kx+1$ is $-3$

Put $x=-3$ in the given polynomial and it must satisfy the polynomial.

$\Rightarrow ( k-1)( -3)^2+k( -3)+1=0$

$\Rightarrow ( k-1)9-3k+1=0$

$\Rightarrow 9k-9-3k+1=0$

$\Rightarrow 6k-8=0$

$\Rightarrow 6k=8$

$\Rightarrow k=\frac{8}{6}$

$\Rightarrow k=\frac{4}{3}$

Therefore, the value of $k$ is $\frac{4}{3}$.

raja
Updated on 10-Oct-2022 13:27:08

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