giúp e với ạ e cảm ơn

`9)`

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

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

`=3x-10`

`10)`

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

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

`=19x+1`

`11)`

`3x(4x-3)-(2x-1)(6x+5)`

`=12x^2 -9x-12x^2 -4x+5`

`=-13x+5`

`12)`

`(2-5x)(3-4x)+x(2x+23)`

`=6-23x+20x^2 +2x^2 +23x`

`=6+22x^2`

`13)`

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

`=3x^2 -9x+6+3x^3 -2x^2 -x`

`=3x^3 - x^2 - 10x+6`

`14)`

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

`=-4x^3 +4x^2 +48x-3x^3 +3x^2 -3x`

`=-7x^3 +7x^2 +45x`

`15)`

`-3(x+4)(x-7)+7(x-5)(x-1)`

`=-3x^2 +9x+84+7x^2 -42x+35`

`=4x^2 -33x+119`

`16)`

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

`=-4x^3 -2x+12x^2 +6+4x^3 +9x^2 +2x`

`=21x^2 +6`.