Problema 7si 8 pls repede

a-b=34710
b/a=4/7 ==> 7b=4a
4(a-b)=4 ori 34710
4a-4b=138840
4a=7b
7b-4b=138840
3b=138840
b=138840/3
b=46280
a=b+34710
a=46280+34710
a=80990