3 2/45х+1 7/30х=6 1/9
(3*45+2)/45x+(1*30+7)/30x=(6*9+1)/9
137x/45+37x/30=55/9 |*90
274x+111x=550
385x=550
x=550/385=110/77=10/7
(8 2/5/x+3 5/9)/4 1/6=1 1/3
(42/(5x)+32/9)/ (25/6)=4/3
42/(5x)+32/9=4/3*25/6
42/(5x)=50/9-32/9
42/(5x)=2
5x=42/2=21
x=21/5=4.2
