#### Answer

x=-3 or 5

#### Work Step by Step

Factor the trinomial.
x$^2$-2x-15=0
(x+3)(x-5)=0
Set each variable factor as equal to zero and then isolate the variable to find the solutions.
x+3=0 or x-5=0
x=-3 or x=5
Enter the original equation into your graphing utility to observe that the graph crosses the x-axis at -3 and 5.