Answer
Add $9$ to both sides of the equation
Work Step by Step
$x^2 + 6x = 7$
The coefficient of the x-term is $6$.
Half of $6$ is $3$, and $3^2 = 9$.
Thus, add $9$ to both sides of the equation to complete the square.
$x^2 + 6x +9 = 7 +9$
$x^2 + 6x +9 = 16$
$(x+3)^2 = 16$
$ x +3 =\sqrt16$ or $ x +3 =-\sqrt16$
$x = -3+\sqrt16$ or $x = -3-\sqrt16$
The solutions are $-3±\sqrt16$.
