Answer
The solution is -7.
Work Step by Step
$x^{2}$+14$x^{}$+49=0
$x^{2}$+7$x^{}$+7x+49=0
(x+7)+7(x+7)=0
(x+7)(x+7)=0
x+7=0 or x+7=0
x=-7 or x=-7
The solution is -7.
Check
Let x=-7
$x^{2}$+14$x^{}$+49=0
$(-7)^{2}$+14(-7)+49=0
49-98+49=0
0=0