(7x^3-2x^2):(-2x^2)+(5/4x^2-3x):x-1/2x.(x-1).(2x+1)

Đáp án:

`-x^{2}-7/4x-3/2`

Lời giải:

`(7x^{3}-2x^{2}):(-2x^{2})+(5/4x^{2}-3x):x-1/2x.(x-1).(2x+1)` `(đk: x\ne0)`

`=[7x^{3}:(-2x^{2})+(-2x^{2}):(-2x^{2})]+[(5/4x^{2}:x)-(3x:x)]-(x-1).(x^{2}+1/2x)`

`=(-7/2x)+1+5/4x-3-(x^{3}+1/2x^{2}-x^{2}-1/2x)`

`=-2+(5/4x-7/2x)-(x^{3}-1/2x^{2}-1/2x)`

`=(-2)+(-9/4x)-x^{3}+1/2x^{2}+1/2x`

`=(-9/4x+1/2x)-x^{3}+1/2x^{2}-2`

`=-x^{3}+1/2x^{2}-7/4x-2`