(х+58)-37=91. (63-у)+109=121. 69-(у-28)=13. 103-(z+47)=54

1) (х+58)-37=91
х+58 = 91+37
х = 128 - 58
х = 70
2) (63-у)+109 = 121
63-у = 121-109
63-у = 12
у = 63-12
у = 51
3) 63-(у-28)=13
63-у+28=13
-у = 13-63-28
-у = -78
у = 78
4) 103-(z+47)=54
103-z-47 = 54
-z = 54-103+47
-z = -2
z = 2