Answer
The solution is -5.
Work Step by Step
$x^{2}$+10x=-25
$x^{2}$+10x+25=-25+25
$x^{2}$+10x+25=0
$x^{2}$+2*5*x+$5^{2}$=0
$(x+5)^{2}$=0
x+5=0
x+5-5=0-5
x=-5
The solution is -5.
Check
Let x=-5
$x^{2}$+10x=-25
$(-5)^{2}$+10(-5)=-25
25-50=-25
-25=-25
