Question

If one root of the quadratic equation, $x^2-7x+k=0$ is $5$, then find the value of $k$.

Answer 1

Given one root of the quadratic equation $x^2-7x+k=0$ is $5$.
$\therefore$ Substituting $x=5$ in the given equation, we have
$x^2-7x+k=0$ is $5$.
$\therefore$ Substituting $x=5$ in the given equation, we have
$x^2-7x+k=0$
${\left(5\right)}^2-7\left(5\right)+k=0$
$\therefore$ $25-35+k=0$
$\therefore$ $-10+k=0$
$\therefore$ $k=10$