The equations are

Multiply the first equation by 2

Now the equation is

                   Equation (1)

Since the coefficients of the x-terms, +10 and +10, are additive inverses,

you can eliminate these terms by adding the equations. .

subtract the equations to eliminate variable y.

(Write the equations in column form and subtract)

x = 9

Now Substitute x = 9 for x  in either equation to find the value of y.

         (Equation 2)

             (Multiply: )

Apply subtraction property of equality: Subtract 27 from each side.

Apply commutative property of addition: a + b = b + a.

         (Apply additive inverse property: )

               (Subtract: )

Apply division property of equality: Divide each side by 10.

                   (Cancel common terms)

                        (Divide: )

The solution is .

The solution is .