Решите уравнения:
1) 5 3/7-(b-2 1/7)=2 4/7
2) (270:y-12)*70=1260

1) 5 3/7-(b-2 1/7)=2 4/7
38/7 - b + 15/7 = 18/ 7
b = 38/7 + 15/7 -18/7
b = 38+15-18 /7
b = 35/7
b = 5



2) (270:y-12)*70=1260
(270:y-12)=1260÷70
270÷y-12= 18
270÷y = 18+12
270÷y = 30
y = 270÷30
y = 9

(5*7+3)/7-7*b/7+(2*7+1)/7=(2*7+4)/7
38-7b+15=18
-7b=18-15-38
b=-1*(18-15-38)/(7)
b=35/7=5

270*70/y-840=1260
18900/y=1260+840=2100
y=18900/2100=9