Đáp án:

 

Giải thích các bước giải:

 `1,1/[x-1]-[5x-4]/[x^2 -x]`

`= 1/[x-1]+[4-5x]/[x(x-1)]`

`=[x+4-5x]/[x(x-1)]`

`=[-4x+4]/[x(x-1)]`

`=[-4(x-1)]/[x(x-1)]`

`=-4/x`

`2,1/[3x-2]-4/[3x+2]-[3x-6]/[4-9x^2]`

`=1/[3x-2]-4/[3x+2]+[3x-6]/[(3x-2)(3x+2)]`

`=[3x+2-4(3x-2)+3x-6]/[(3x-2)(3x+2)]`

`=[3x+2-12x+8+3x-6]/[(3x-2)(3x+2)]`

`=[-6x+4]/[(3x-2)(3x+2)]`

`=[-2(3x-2)]/[(3x-2)(3x+2)]`

`=-2/[3x+2]`

`3,[x+1]/[x-2].[x^2 -4]/[(x+1)^2]`

`=[x+1]/[x-2].[(x-2)(x+2)]/[(x+1)^2]`

`=[x+2]/[x+1]`

`4,[3-3x]/[x^2 -9].[x-3]/[x-1]`

`=[-3(x-1)]/[(x-3)(x+3)].[x-3]/[x-1]`

`=-3/[x+3]`

`5,[x-2]/[x+1].[2x^2 -5x-3]/[x^2 -5x+6]`

`=[x-2]/[x+1].[2x^2 -6x+x-3]/[x^2 -2x-3x+6]`

`=[x-2]/[x+1].[(x-3)(2x+1)]/[(x-2)(x-3)]`

`=[x-2]/[x+1].[2x+1]/[x-2]`

`=[2x+1]/[x+1]`

(Bài tham khảo)

Đáp án + giải thích :