(149-y)+21=92
(y-72)+84=105

(149-y)+21=92

149 - y + 21 = 92

170 - y = 92

y = 170 - 92

y = 78

(y-72)+84=105

y - 72 + 84 = 105

y + 12 = 105

y = 105 - 12

y = 93