The equations are

                                 Equation (1)

                                  Equation (2)

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

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

\ \

                           (Divide each side by 2)

                                          (Cancel commen terms) \ \

                                  (Divide: )

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

                             (Equation 1)

                             (substituted s = 4)

Apply subtraction proparty: If a = b then a - c = b - c

                    (Subtract 3 from each side)

                  (commutative proparty: ) \ \

                                   (Additive inverse proparty: ) \ \

                                (Subtract:

                               (Multiply each side by negative one) \ \

The solution is \ \