12:х=13-10
12:х=3
х=12:3
х=4
12:х+10=13
12/х + 10 = 13
12/х = 13 - 10
12/х = 3
12= 3х
х= 12÷3
12÷4+10=13
13=13
12:х=13-10
12:х=3
х=12:3
х=4
12:х+10=13
12/х + 10 = 13
12/х = 13 - 10
12/х = 3
12= 3х
х= 12÷3
х=4
12÷4+10=13
13=13