3)13600:z=3876-3851
13600:z=3876-3851
13600:z=25
z=13600:25
z=544
Ответ:544
4)(2865+r)*
125=542875
2865+r=542875:125
2865+r=4343
r=4343-2865
r=1478
Ответ:1478
2х-7х/9=22
18х-7х=198
11х=198
х=198/11
х=18