Упростите выражение.

1) (x+2) * (x-5) - 3x * (1-2x) = x - 5x + 2x - 10 - 3x + 6x = 7x - 6x - 10

2) (a+3) * (a-2) + (a-3) * (a+6) = a - 2a + 3a - 6 + a + 6a - 3a - 18 = 2a + 4a - 24

3) (x-7) * (3x-2) - (5x+1) * (2x-4) = 3x - 2x - 21x + 14 - (10x - 20x + 2x - 4) = 3x - 2x - 21x + 14 - (10x - 18x - 4) = 3x - 2x - 21x + 14 - 10x + 18x + 4 = -7x - 5x + 18

4) (5x-2y) * (3x+5y) - (2,5x - 3y) * (4x + 8y) = 15x + 25xy - 6xy - 10y - (10x + 20xy - 12xy - 24y) = 15x + 25xy - 6xy - 10y - (10x + 8xy - 24y) = 15x + 25xy - 6xy - 10y - 10x - 8xy + 24y = 5x + 11xy + 14y

5) (3a + 5y) * (2a + y) - 7a * (a - 3y) = 6a + 3ay + 10ay + 5y - 7a + 21ay = -a + 3ay + 31ay + 5y.

Если что то не понятно спрашивай!!!!