Упростите выражение: 2 (a-3) + 3a+b 4 (0,3x-2y) + 7,8x-y 3 (2c-3d) + 2 (2,5c-d) 5 (3x+y) + 2 (7x+12y)

1) 2 (a - 3) + 3a + b = 2 а - 6 + 3 а + b = 5 а - 6 + b;

2) 4 (0,3x - 2y) + 7,8x - y = 1,2x - 8y + 7,8x - у = 9 х - 8 у - у = 9 х - 9 у = 9 (x - y);

3) 3 (2c - 3d) + 2 (2,5c - d) = 6 с - 9d + 5c - 2d = 11c - 9d - 2d = 11c - 11d = 11 (c - d);

4) 5 (3x+y) + 2 (7x + 12y) = 15x + 5y + 14x + 24y = 29x + 5y + 24y = 29x + 29y = 29 (x + y).