Question

Tính (rút gọn )

1, 2x(3x-1)-(2x+1)(x-3)

2,  3(x^2-2x)-(4x+2)(x-1)

3, 3x(x-5)-(x-2)^2 -(2x+3)(2x-3)

4,  (2x-3)^2+(2x-1) (x+4)

 

Answer 1

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

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

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

2) `3(x^2-3x)-(4x+2)(x-1)`

`=3x^2-9x-4x^2+4x-2x+2`

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

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

`=3x^2-15x-(x^2-4x+4)-(4x^2-9)`

`=3x^2-15x-x^2+4x-4-4x^2+9`

`=-2x^2-11x+5`

4) `(2x-3)^2+(2x-1)(x+4)`

`=4x^2-12x+9+2x^2+8x-x-4`

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