4/5•х=12. 3/7•х=11/10
1) 4/5 * x = 12 x = 12 : 4/5 x = 12 * 5/4 x = 15 2) 3/7 * x = 11/10' 11/10 : 3/7 11/10 : 7/3 x = 77/30