Номер 1185

1) – 4 + 5 – 9 = – 4 + (5 – 9) = –4 – (–5 + 9)

2) p – a + 7 = p + (–a + 7) = p – (a – 7)

3) 9 – a – b = 9 + (–a –b) = 9 – (a + b)

4) a + t + m = a + (t + m) = a – (–t – m)