a + x/2 + b + x/2 = c + x
x = 260
x/2 = 130
a + 130 + b + 130 = c + 260
a + b + 260 = c + 260
a + b = c
ответ: 130
a + x/2 + b + x/2 = c + x
x = 260
x/2 = 130
a + 130 + b + 130 = c + 260
a + b + 260 = c + 260
a + b = c
ответ: 130