2/3. Упростить: (2m - 4m + 5m = -1,3a + 4a - 3,7a = 4x - 8y - 6x + 11y = (a-2) + (a-3) - (-2a+7) = 2.(a-3) - (5a+6) = -3(2x-9) + (-5x+1) = (2x-3) + (x-5) - (7-3x) = -2.(m-3) - (3m-5) =

Решение:

1. \(2m - 4m + 5m = (2 - 4 + 5)m = 3m\)
2. \(-1,3a + 4a - 3,7a = (-1,3 + 4 - 3,7)a = -1a = -a\)
3. \(4x - 8y - 6x + 11y = (4 - 6)x + (-8 + 11)y = -2x + 3y\)
4. \((a-2) + (a-3) - (-2a+7) = a - 2 + a - 3 + 2a - 7 = (1 + 1 + 2)a + (-2 - 3 - 7) = 4a - 12\)
5. \(2(a-3) - (5a+6) = 2a - 6 - 5a - 6 = (2 - 5)a + (-6 - 6) = -3a - 12\)
6. \(-3(2x-9) + (-5x+1) = -6x + 27 - 5x + 1 = (-6 - 5)x + (27 + 1) = -11x + 28\)
7. \((2x-3) + (x-5) - (7-3x) = 2x - 3 + x - 5 - 7 + 3x = (2 + 1 + 3)x + (-3 - 5 - 7) = 6x - 15\)
8. \(-2(m-3) - (3m-5) = -2m + 6 - 3m + 5 = (-2 - 3)m + (6 + 5) = -5m + 11\)

Ответ: 1. 3m; 2. -a; 3. -2x + 3y; 4. 4a - 12; 5. -3a - 12; 6. -11x + 28; 7. 6x - 15; 8. -5m + 11.