The equations are

Since the coefficients of the x-terms +4 and +4 are same,

you can eliminate these terms by subtracting the equations.

Subtract the equations to eliminate variable x.

(Write the equations in column form and subtract)

Apply division property of equality: Divide each side by negative 12.

                                         (Cancel common terms)

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

  (Equation 1)                           

                          (Multiply:  )

Apply addition property of equality: Add 9 to each side.

              (Additive inverse property: )

                     (Additive identity property: )

                           (Add: )

Apply division property of equality: Divide each side by 4.

                           (Cancel common terms)

                                (Divide: )

The solution is .

The solution is .