Did your answer include any of the following?
a. Eliminate y by adding equations (1) and (3) because the coefficients on y are opposites. Then eliminate y by multiplying equation (1) by 2 and adding it to equation (2).
b. Eliminate z by subtracting equations (1) and (2) because the coefficients are the same. Then eliminate z by multiplying equation (3) by 2 and adding it to equation (1).
c. The variables have to be the same in both equations in the 2 × 2 system.