Answer
The solutions are -5 and 3.
Work Step by Step
$x^{2}$+2x-15=0
$x^{2}$+5x-3x-15=0
x(x+5)-3(x+5)=0
(x-3)(x+5)=0
x-3=0 or x+5=0
x-3+3=0+3 or x+5-5=0-5
x=3 or x=-5
The solutions are -5 and 3.
Chec
Let x=-5
$(-5)^{2}$+2(-5)-15=0
25-10-15=0
0=0
Let x=3
$x^{2}$+2x-15=0
$3^{2}$+2*3-15=0
9+6-15=0
0=0
