) 5/7у – 24 = 8/21у – 15
в) 0,6 (5х – 7) = 3 (0,4х + 6,4)

1) 5/7у-24=8/21у-155/7у-8/21у=24-1515/21у-8/21у=97/21у=9у=9:7/21у=9 * 21/7у=189/7у=272)0,6(5х-7)=3(0,4х+6,4)3х-4,2=1,2х+19,23х-1,2х=19,2+4,21,8х=23,4х=23,4:1,8х=13