Solve for both systems 3x + 6z = 45 and 10x+5z=90

3x + 6z = 45

3x + 6z-6z = 45 -6z

3x= 45 -6z

3x/3= 45 -6z/3

x=15-2z

10x+5z=90

10(15-2z)+5z=90

10(15) (10)(-2z)+5z=90

150-20z+5z=90

150-15z=90

150-150-15z=90-150

-15z=-60

-15z/-15=-60/-15

z=4

x=15-2z

x=15-2(4)

x=15-8=7