[(72:a-3×4)×36-19×5] - (124×6-301×2) = 195
[(72:a-12) × 36-95] - (744 - 602) = 195
[(72 : a -12) × 36 -95] - 142 = 195
(72 : a -12) × 36 -95 = 195 + 142
(72 : a -12) × 36 -95 = 337
(72 : a - 12) × 36 = 337 + 95
(72 : a - 12) × 36 = 432
72 : a - 12 = 432 : 36
72:a - 12 = 12
72 : a = 12+12
72 : a = 24
a = 72 : 24
a = 3
