1.Сделайте деяние: а) 15y+7y-(13y-5y). б) 2c(a-3b+4). в) (4x-1)(2x-3). г) (a+2)(a-a-3). д)

1.а) 15y + 7y - (13y - 5y) = 15y + 7y - 13y + 5y = y (15 + 5) + y (7 - 13) = 20y - 6y.

б) 2c (a - 3b + 4) = 2c * a - 3b * 2c + 4 * 2c = 2ac - 6bc + 8c.

в) (4x - 1) (2x - 3) = 4x * 2x - 3 * 4x - 1 * 2x + 1 * 3 = 8x - 12x - 2x + 3 = 8x - x (12 + 2) + 3 = 8x - 14x + 3.

г) (a + 2) (a - a - 3) = a * a - a * a - 3 * a + 2 * a - 2 * a - 3 * 2 = a - a - 3a + 2a - 2a - 6 = a + a (2 - 1) + a (- 3 - 2) - 6 = a + a - 5a - 6.

д) (4ab - 6ab) : 2ab = 4ab/2ab - 6ab/2ab = 2b - 3a.

2. Раскроем по правилам наши скобки и приведем сходственные слагаемые.

2x (3x - 4) - 3x (3x - 1) = 2x * 3x - 4 * 2x - 3x * 3x + 1 * 3x = 6x - 8x - 9x + 3x = x (6 - 9) + x (- 8 + 3) = - 3x - 5x.

3. 1,5x (3x - 5) (2x + 3) = 1.5x (3x * 2x + 3 * 3x - 5 * 2x - 5 * 3) = 1.5x (6x + 9x - 10x - 15) = 1.5x (6x - x - 15) = 1.5x * 6x - 1.5x * x - 1.5x * 15 = 9x5 - 1.5x - 22.5x.

4. 5a (a + b + c) - 5d (a - b - c) - 5c (a - b - c) = 5a * a + 5a * b + 5a * c - 5d * a + 5d * b + 5d * c - 5c * a + 5c * b + 5c * c = 5a + 5ab + 5ac - 5ad + 5bd + 5dc - 5ac + 5bc + 5c = 5a + 5ab - 5ad + 5bd + 5dc + 5bc + 5c.