,

Subtract from both sides of the equation.

Replace all occurrences of in with .

Simplify .

Simplify each term.

Apply the distributive property.

Multiply by .

Multiply by .

Subtract from .

Move all terms not containing to the right side of the equation.

Subtract from both sides of the equation.

Subtract from .

Divide each term by and simplify.

Divide each term in by .

Cancel the common factor of .

Cancel the common factor.

Divide by .

Cancel the common factor of and .

Factor out of .

Cancel the common factors.

Factor out of .

Cancel the common factor.

Rewrite the expression.

Replace all occurrences of in with .

Simplify .

Simplify each term.

Cancel the common factor of .

Factor out of .

Cancel the common factor.

Rewrite the expression.

Multiply by .

Subtract from .

The solution to the system is the complete set of ordered pairs that are valid solutions.

The result can be shown in multiple forms.

Point Form:

Equation Form:

Solve by Substitution x+3y=9 , 3x-3y=-13