(х+155)-35=145
х+155=145+35
х+155=180
х=180-155
х=25
168-(98+z)=65
98+z=168-65
98+z=103
z=103-98
z=5
(853+у)-53=900
853+у=900+53
853+у=953
у=953-853
у=100
(s+275)-275=384
s+275=384+275
s+275=659
s=659-275
s=384
0,9(0,4-1 2/3m)-0,2(0,8-7 1/2m) = 9/10 (2/5 - 5/3 m ) - 1/5 ( 4/5 - 15/2m ) = 9/25 - 3/2m - 4/25 + 3/2m = 9-4/25 = 5/25 = 1/5
36/9=4л за 1 минуту
4*15=60л.