Answer
x=-3 or 6
Work Step by Step
Rewrite the equation so it is in standard form.
x(x-3)=18
x$^2$-3x=18
x$^2$-3x-18=0
Factor the trinomial.
(x+3)(x-6)=0
Set each variable factor as equal to zero and then isolate the variable to find the solutions.
x+3=0 or x-6=0
x=-3 or x=6
Enter the equation into your graphing utility to observe that the graph crosses the x-axis at -3 and 6.