Раскройте скобки: a) a + (-3b + 2c) б) -x - (-3p - 2y) в) – (m - 2n) + (3a + b) г) (x – 5) – (7 – x) + (9 – x)

а) a + (-3b + 2c) = a - 3b + 2c = **a - 3b + 2c** б) -x - (-3p - 2y) = -x + 3p + 2y = **-x + 3p + 2y** в) – (m - 2n) + (3a + b) = -m + 2n + 3a + b = **-m + 2n + 3a + b** г) (x - 5) - (7 - x) + (9 - x) = x - 5 - 7 + x + 9 - x = (x + x - x) + (-5 - 7 + 9) = x - 3 = **x - 3**