b=3
Пошаговое объяснение:
1.
b+13= 13, 14, 15, 16, 17, 18.
19-b= 19, 18, 17, 16, 15, 14.
2.
b+13=19-b
b+b=19-13
2b=6
b=6/2=3
b=3
Пошаговое объяснение:
1.
b+13= 13, 14, 15, 16, 17, 18.
19-b= 19, 18, 17, 16, 15, 14.
2.
b+13=19-b
b+b=19-13
2b=6
b=6/2=3