Solve each system by elimination. Check your answers.
13. { 6q - r + 2s = 8
{ 2q + 3r - s = -9
{ 4q + 2r + 5s = 1
14. { x - y + 2z = -7
{ y + z = 1
{ x = 2y + 3z
Please explain well for how you figured out the problems, thanks!