60÷4=15 1-тесьма 15см, 2-тесьма 15×3=40см.
15-10у-36+4у=3у+15
-6у-3у=15+36-15
-9у=36
у=-4
1) 570×X-4700=13540
570Х-4700=13540
570Х=13540+4700
570Х=18240
Х=18240:570
Х=32
2) 340×X-416×2=18208
340Х=18208+416×2
340Х=19040
Х=19040:340
Х=56
3) (223440 - 130 × X) : 35=6020
(223440 - 130X) = 6020 × 35
223440 - 130X = 210700
130Х = 223440 - 210700
130Х = 12740
Х = 12740 : 130
Х = 98
4) (31 × 550 - X) × 120=10200
(31 × 550-X) = 10200 : 120
31 × 550 - X = 85
Х = 31 × 550 - 85
Х = 17050 - 85
Х = 16965