Question

If $x=3$ is one root of the quadratic equation $x^2-2kx-6=0$, then find the value of $k$.

Answer 1

Given it's one root of the equation $x^2-2kx-6=0$

one of it's root $x=3$

for finding the value of $k$ put the value of $x$ in thiss equation.

$\begin{array}{c}\Rightarrow (3{)}^2-2k\left(3\right)-6=0\\ \Rightarrow 9-6k-6=0\\ \Rightarrow 6k=3\\ \Rightarrow k=\frac{3}{6}\\ \Rightarrow k=\frac{1}{2}\end{array}$

hence,

the value of $k=\frac{1}{2}$