x+320=560
x-240 = 0
x = 240
проверка
240+320=80*7
560=560
x-180=240:3
x-180=80
х=80+180
х=260
260-180=240:3
80=80
400 – x = 275 + 25
– x = 25 + 275 – 400
-x = -100
x = 100
400-100=275+25
300=300
x+320=560
x-240 = 0
x = 240
проверка
240+320=80*7
560=560
x-180=240:3
x-180=80
х=80+180
х=260
проверка
260-180=240:3
80=80
400 – x = 275 + 25
– x = 25 + 275 – 400
-x = -100
x = 100
проверка
400-100=275+25
300=300