7 1/14-х= 9 3/8
х= 7 1/14- 9 3/8
х=99/14-75/8
х=396/56-525/56
х=-129/56=-2 17/56
проверка
7 1/14- (-2 17/56)= 9 3/8
7 1/14+ 2 17/56=9 3/8
99/14+129/56= 9 3/8
396/56+ 129/56=9 3/8
525/56= 9 21/56=9 3 /8
2) 1 : 2 7/9= х+ 4 2/5х
1: 25/9= х+ 22/5х
1* 9/25=5/5х+22/5х
9/25= 27/5х
х= 9/25: 27/5
х= 9/25 * 5 /27
х=1/5 * 1/3=1/15
прповерка
1*9/25= 5/5*1/15+22/5*1/15
9/25=5/75+22/75
9/25=27/75
9/25=9/25
