Solve for each of the systems 2z+5x=42 and 2z + 10x = 72

2z + 10x = 72

2z + 10x-10x = 72-10x

2z= 72-10x

2z/2= 72-10x/2

z=36-5x

2z+5x=42

2(36-5x)+5x=42

2(36) (2)(-5x)+5x=42

72-10x+5x=42

72-5x=42

72-5x-72=42-72

-5x=-30

-5x/-5=-30/-5

x=6

z=36-5x

z=36-5(6)

z=36-30=6