45-72:х=9 15у-2у+у=84 4z-z-7=20

Question

45-72:х=9 15у-2у+у=84 4z-z-7=20

Answer 1

45-72x=9
-72x=9-45
-72x=-36
x=-36:(-72)
x=0,5

15-2у+у=84
14у=84
 у=84:14
у=6

4z-z-7=20 
3z=20+7
z=27:3
z=9