The equation is
.
The perfect square of the given trinomial
.

(Take the square root of each side)
Apply square roots property: If
then
.


Apply subtraction property of equality: If a = b then a
c = b
c.
(Subtract 8 from each side)
(Apply additive inverse property:
)
Using the calculator and evaluate square roots.
\
Separate the solutions
.

The solution set is
.