,

Subtract from both sides of the equation.

Subtract from both sides of the equation.

Multiply each term in by .

Multiply .

Multiply by .

Multiply by .

Simplify each term.

Multiply by .

Multiply .

Multiply by .

Multiply by .

Create a graph to locate the intersection of the equations. The intersection of the system of equations is the solution.

Solve by Graphing x+y=8 , x-y=4