1) 32:(a:9)=4
32 / (1/9a) = 4
32 / а/9 = 4
32 * 9/а = 4
288/а = 4
288 = 4а
4а = 288
а = 72
2) 7*y-23=42
7у = 42 + 23
7у = 65
у = 65/7
3) 8*(250:x+12)=136
8(250/х + 12) = 136
250/х + 12 = 17
250/х = 17-12
250/х = 5
250 = 5х
5х = 250
х = 50
4) (900-a:6)-12=8400
(900 - 1/6а) - 12 = 8400
900 - 1/6а - 12 = 8400
888 - 1/6а = 8400
5328 - а = 50400
-а = 50400 - 5328
-а = 25072
а = -45072
5) 560:(13-x)+20=100
560/13-х + 20 = 100
560/13-х = 100-20
560 = 80(13-х)
7 = 13 - х
х = 13 - 7
х = 6
6) 810:(a-3-60)=9
810/а-63 = 9
810 = 9(а - 63)
90 = а-63
-а = -153
а = 153
