Question:
Very-Short-Answer Questions
If $x=\frac{-1}{2}$ is a solution of the quadratic equation $3 x^{2}+2 k x-3=0$, find the value of $k$.
Solution:
It is given that $x=\frac{-1}{2}$ is a solution of the quadratic equation $3 x^{2}+2 k x-3=0$.
$\therefore 3 \times\left(\frac{-1}{2}\right)^{2}+2 k \times\left(\frac{-1}{2}\right)-3=0$
$\Rightarrow \frac{3}{4}-k-3=0$
$\Rightarrow k=\frac{3-12}{4}=-\frac{9}{4}$
Hence, the value of $k$ is $-\frac{9}{4}$.