If one zero of the quadratic polynomial

Question:

If one zero of the quadratic polynomial $k x^{2}+3 x+k$ is 2 , then the value of $k$ is

(a) $\frac{5}{6}$

(b) $\frac{-5}{6}$

(c) $\frac{6}{5}$

(d) $\frac{-6}{5}$

 

Solution:

(d) $\frac{-6}{5}$

Since 2 is a zero of $k x^{2}+3 x+k$, we have:

$k \times(2)^{2}+3 \times 2+k=0$

$=>4 k+k+6=0$

$=>5 k=-6$

$=>k=\frac{-6}{5}$

 

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