`1) (4x + 1)(2 - x) - 7x`

`= 8x - 4x^2 + 2 - x - 7x`

`= -4x^2 + (8x - x - 7x) + 2`

`= -4x^2 + 2`

`2) (3x - 1)(2 - 2x) - 5x`

`= 6x - 6x^2 - 2 + 2x - 5x`

`= -6x^2 + (6x + 2x - 5x) - 2`

`= -6x^2 + 3x - 2`

`3) (3x - 2)(3x + 2) - 9x^2`

`= (9x^2 - 4) - 9x^2 = -4`

`4) (2x - 3)(2x + 3) - 4x^2`

`= (4x^2 - 9) - 4x^2 = -9`

`5) (x + 2)(x - 3) + x(x + 1)`

`= (x^2 - 3x + 2x - 6) + (x^2 + x)`

`= x^2 - x - 6 + x^2 + x`

`= 2x^2 - 6`

`6) (2x - 1)(x + 1) + x(2x - 5)`

`= (2x^2 + 2x - x - 1) + (2x^2 - 5x)`

`= 2x^2 + x - 1 + 2x^2 - 5x`

`= 4x^2 - 4x - 1`

`7) x(1 - x) + (x + 1)(x - 2)`

`= x - x^2 + (x^2 - 2x + x - 2)`

`= x - x^2 + x^2 - x - 2`

`= -2`

`8) (3x - 1)(x + 4) - 3x(x - 1)`

`= (3x^2 + 12x - x - 4) - (3x^2 - 3x)`

`= 3x^2 + 11x - 4 - 3x^2 + 3x`

`= 14x - 4`

`9) 2x(x - 3) + (x - 2)(5 - 2x)`

`= (2x^2 - 6x) + (5x - 2x^2 - 10 + 4x)`

`= 2x^2 - 6x - 2x^2 + 9x - 10`

`= 3x - 10`

`10) 6x(2x + 3) - (3x - 1)(4x + 1)`

`= (12x^2 + 18x) - (12x^2 + 3x - 4x - 1)`

`= 12x^2 + 18x - (12x^2 - x - 1)`

`= 12x^2 + 18x - 12x^2 + x + 1`

`= 19x + 1`