50 * (х:16) = 40 150
х :16 = 40 150 : 50
х :16 = 803
х = 803 * 16
х = 12 848
2 700 + у*400 = 170 700
у*400 = 170 700 - 2 700
у*400 = 168 000
у = 168 00 : 400
у = 420
(12 030 - 30) : к = 30
12 000 : к = 30
к = 12000 : 30
к = 400
(а + 109) * 30 = 6 510
а +109 = 6 510 : 30
а + 109 = 219
а = 219 - 109
а = 100
d - (240*13) = 1260
d - 3120 = 1260
d = 1260+3120
d = 4380
n+1240 = 1060 *20
n+1240 = 21200
n = 21200 - 1240
n = 19 960