Solve for both systems z+7y=38 and 3z + y = 54

z+7y=38

z+7y-7y=38 -7y

z=38 -7y

3z + y = 54

3(38 -7y) + y = 54

3(38) (3)( -7y) + y = 54

114 -21y + y = 54

114 -2y= 54

114 -2y-114= 54-114

-2y=-60

-2y/-2=-60/-2

y=30

z=38 -7y

z=38 -7(30)

z=38 -210

z=-172