Question

If one root of the quadratic equation $3x^2-kx-2=0$ is $2$, find the value of ‘$k$’.

Answer 1

Find the value of $k$:

Given quadratic equation is $3x^2-kx-2=0$

If one root is 2, it must satisfy the given equation.

$\begin{array}{rcl}& \Rightarrow & 3{\left(2\right)}^2-k\left(2\right)-2=0\\ & \Rightarrow & 3\times 4-2k-2=0\\ & \Rightarrow & 12-2k-2=0\\ & \Rightarrow & 2k=10\\ & \Rightarrow & k=\frac{10}{2}\\ \therefore k& =& 5\end{array}$

Hence, the value of $k$ is 5.