11Р+42-11Р=78
11Р-11Р=78-42
11Р-11Р=36
Р=36
11p+42-2p+9p=100-22
18р=100-22-42
18р=36
р=2
проверка 11*2+42-2*2+9*2=78
100-22=78
78=78
11Р+42-11Р=78
11Р-11Р=78-42
11Р-11Р=36
Р=36
11p+42-2p+9p=100-22
18р=100-22-42
18р=36
р=2
проверка 11*2+42-2*2+9*2=78
100-22=78
78=78