Solve for both systems z + y = 12 and 11z+6y=132

z + y = 12

z-z + y = 12-z

y = 12-z

11z+6y=132

11z+6(12-z)=132

11z+6(12) (6)(-z)=132

11z+72-6z=132

5z+72=132

5z+72-72=132-72

5z=60

5z/5=60/5

z=12

y = 12-z

y = 12-12=0