15с + 45 - 12 = 78
15с+33 = 78
15с=78-33
15с=45
с = 45:15
с=3
(6у+14):2+15 =40
(6у+14):2 = 40-15
(6у+14):2 = 25
6у+14 = 25*2
6у+14 = 50
6у=50-14
6у=36
у=36:6
у=6
16x+5=133
16х = 133-5
16х=128
х=128 :16
х=8
42k-28k+180=600
14к+180=600
14к=600-180
14к=420
к=420:14
к=30
8у *5 = 56*5
8у*5 = 280
8у = 280:5
8у = 56
у=56:8
у=7
147а - 49= (9+26)*7
147а -49 = 245
147а = 245 +49
147а = 294
а=294 :147
а=2