Answer
$x=1$ and $x=-15$.
Work Step by Step
The given equation is
$\Rightarrow x^2+14x=15$
Find the value of $(\frac{b}{2})^2$.
Substitute $14$ for $b$.
$=(\frac{14}{2})^2$
Simplify.
$=(7)^2$
$=49$
Add $49$ to each side of the equation.
$\Rightarrow x^2+14x+49=15+49$
Simplify.
$\Rightarrow x^2+14x+49=64$
Write the left side as the square of a binomial.
$\Rightarrow (x+7)^2=64$
Take the square root of each side.
$\Rightarrow x+7=\pm 8$
Subtract $7$ from each side.
$\Rightarrow x+7-7=\pm 8-7$
Simplify.
$\Rightarrow x=\pm 8-7$
The solutions are $x=8-7=1$ and $x=-8-7=-15$.
