(5 3//8+18 1//2-c):8 1//2=2
(5.375+37//2-c):(8 1//2)-2=0
(23.875-c):(17//2)-2=0
23.875/8.5-c/8.5-2=0
(55//68)-c/8.5=0
c=55//68*8.5
c=6.875
(3 1//2-2 2//3+b+4 3//5)*24=270 2//5
(3.5-8//3+b+4 3//5)*24-270 2//5=0
(5//6+b+4.6)*24-270 2//5=0
130.4+24b-1352//5=0
-140+24b=0
b=140/24
b=35//6
b=5 5//6
// - черта дроби