Question

Câu 1: Thực hiện phép tính

a) (5x + 3)(4x\(^2\) - 6x + 2)

b) \(\frac{x}{2x-2}\) + \(\frac{x-2}{x^2-1}\) - \(\frac{5}{2x+2}\)

Câu 2: Tìm x

(x + 3)(x - 2) - (x\(^3\) -3x\(^2\) + 3x -1) : (x-1)=2

Mong m.n giúp ạ , tối e nộp gấp !!

Answer 1

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

`=5x(4x^2-6x+2)+3(4x^2-6x+2)`

`=20x^3-30x^2+10x+12x^2-18x+6`

`=20x^3(-30x^2+12x^2)+(10x-18x)+6`

`=20x^3-18x^2-8x+6`

`b,x/(2x-2)+(x-2)/(x^2-1)-5/(2x+2)` `Đkxđ: x ≠ +-1`

`<=>x/(2(x-1))+(x-2)/((x+1)(x-1))-5/(2(x+1))`

`<=>(x(x+1)+2(x-2)-5(x-1))/(2(x-1)(x+1))`

`<=>(x^2-2x+1)/(2(x-1)(x+1))`

`<=>(x-1)/(2(x+1))`

`2,(x+3)(x-2)-(x^3-3x^2+3x-1):(x-1)=2`

`<=>(x+3)(x-2)-(x^3-3x^2+3x-1)/(x-1)=2`

`<=>(x+3)(x-2)-(x-1)^2=2`

`<=>x^2-2x+3x-6-x^2+2x-1=2`

`<=>3x-7=2`

`<=>x=3`

Vậy `S={3}`