The equations are

                             Equation (1)

                                  Equation (2)

Since the coefficients of the y-terms are additive inverses, you can eliminate these terms by adding the equations.  Add the equations to eliminate variable y.

Write the equations in column form and add the corresponding columns.

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                           (Divide each side by 2)

                                  (Cancel commen terms)

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

                             (Equation 1)

                          (Replace x by –1)

Apply addition proparty:If a = b then a + c = b + c

              (Add 1 to each side)

                   (Commutative proparty: ) \ \

                                      (Additive invere proparty: ) \ \

                                   (Add: )

The solution is

The solution is . \ \