Answer to Question #129563 in Algebra for Tommy

Question

If x = 3 is the solution of x^2 + kx +15, value of k is

Answer 1

$x^2+kx+15=0$

If $x=3$ is the solution of this equation, then $3^2+3\times k+15=24+3k=0$ and $k=-8.$

Answer: $k=-8.$