Add to both sides of the equation.

To create a trinomial square on the left side of the equation, find a value that is equal to the square of half of .

Add the term to each side of the equation.

Raise to the power of .

Simplify .

Raise to the power of .

Add and .

Factor the perfect trinomial square into .

Take the square root of each side of the equation to set up the solution for

Remove the perfect root factor under the radical to solve for .

Simplify the right side of the equation.

Rewrite as .

Factor out of .

Rewrite as .

Pull terms out from under the radical.

Remove parentheses.

Add to both sides of the equation.

The result can be shown in multiple forms.

Exact Form:

Decimal Form:

Solve by Completing the Square x^2-4x-8=0