Solve for both systems 9z+7y=171 and 2z + 3y = 64

2z + 3y = 64

2z + 3y-3y = 64-3y

2z= 64-3y

2z/2= 64-3y/2

z=32-1.5y

9z+7y=171

9(32-1.5y)+7y=171

9(32) (9)(-1.5y)+7y=171

288-13.5y+7y=171

288-6.5y=171

288-6.5y-288=171-288

-6.5y=-117

-6.5y/-6.5=-117/-6.5

y=18

z=32-1.5y

z=32-1.5(18)

z=32-27=5