Raise to the power of .

Subtract from both sides of the equation.

Simplify .

Simplify each term.

Rewrite as .

Expand using the FOIL Method.

Apply the distributive property.

Apply the distributive property.

Apply the distributive property.

Simplify and combine like terms.

Simplify each term.

Multiply by .

Move to the left of .

Multiply by .

Add and .

Add and .

Subtract from .

Use the quadratic formula to find the solutions.

Substitute the values , , and into the quadratic formula and solve for .

Simplify the numerator.

Raise to the power of .

Multiply by .

Multiply by .

Add and .

Rewrite as .

Pull terms out from under the radical, assuming positive real numbers.

Multiply by .

Simplify .

The final answer is the combination of both solutions.

Solve Using the Quadratic Formula x^2+(x+3)^2=15^2