,

Add to both sides of the equation.

Divide each term by and simplify.

Divide each term in by .

Cancel the common factor of .

Cancel the common factor.

Divide by .

Simplify each term.

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.

Divide by .

Replace all occurrences of in with .

Simplify each term.

Apply the distributive property.

Multiply by .

Multiply by .

Combine the opposite terms in .

Add and .

Add and .

Since , the equation will always be true.

Always true

Remove any equations from the system that are always true.

Solve by Substitution 3x-9y=21 , -2x+6y=-14