Question

If one root of the quadratic equation , $x^2-9x+k=0$ is $1$, then find the value of $k$.

Answer 1

Given, one root of the quadratic equation $x^2-9x+k=0$ is $1$
$\therefore$ Substituting $x=1$ in the given equation,
$\therefore$ $x^2-9x+k=0$
${\left(1\right)}^2-9\left(1\right)+k=0$
$\therefore$ $1-9+k=0$
$\therefore$ $-8+k=0$
$\therefore$ $k=8$