(63-y)+109=121
63 – y + 109 = 121
– y = 121 – 109 – 63
-y = -51
y = 51
69-(y-28)=13
69 – y + 28 = 13
– y = 13 – 28 – 69
-y = -84
y = 84
103-(z-7)=54
103 – z + 7 = 54
– z = 54 – 7 – 103
-z = -56
z = 56
(63-y)+109=121
63 – y + 109 = 121
– y = 121 – 109 – 63
-y = -51
y = 51
69-(y-28)=13
69 – y + 28 = 13
– y = 13 – 28 – 69
-y = -84
y = 84
103-(z-7)=54
103 – z + 7 = 54
– z = 54 – 7 – 103
-z = -56
z = 56