Answer
The solutions are 0 and -20.
Work Step by Step
$x^{2}$+20x=0
x(x+20)=0
x=0 or x+20=0
x=0 or x+20-20=0-20
x=0 or x=-20
The solutions are 0 and -20.
Check
Let x=0
$x^{2}$+20x=0
$0^{2}$ +20*0=0
0=0
Let x=-20
$x^{2}$+20x=0
$(-20)^{2}$ +20(-20)=0
400-400=0
0=0