Đáp án+Giải thích các bước giải:
`b) B=(a^2+b^2-2ab)/(ab)-(a^2-b^2)/(a+b) (ĐKXĐ: a,b \ne 0)`
`=(a^2+b^2-2ab)/(ab)-((a-b)(a+b))/(a+b)`
`=(a^2+b^2-2ab)/(ab)-(a-b)`
`= (a^2+b^2-2ab-ab(a-b))/(ab)`
`=(a^2+b^2-2ab-a^2b+ab^2)/(ab)`
`d) D=(1/(x^2-x)+1/(x-1)):(x+1)/(x^2-2x+1)(ĐKXĐ: x \ne 0; x\ne ±1)`
`= (1/(x(x-1))+1/(x-1)):(x+1)/((x-1)^2)`
`= (1/(x(x-1))+x/(x(x-1))) . ((x-1)^2)/(x+1)`
`= (1+x)/(x(x-1)). ((x-1)^2)/(x+1)`
`=(x-1)/x`
`f)F= ((x-2)/(x^2-1)-(x-2)/(x^2-2x+1)) . ((1-x^2)/(2x-4))^2 (ĐKXĐ: x\ne ±1, x\ne 2)`
`= ((x-2)/((x+1)(x-1))-(x-2)/((x-1)^2)).((1-x^2)^2)/((2x-4)^2)`
`=((x-2)(x-1))/((x+1)(x-1)^2)-((x-2)(x+1))/((x+1)(x-1)^2) . ((x^2-1)^2)/((2x-4)^2)`
`= (x^2-x-2x+2-x^2-x+2x+2)/((x+1)(x-1)^2) . ([(x-1)(x+1)]^2)/((2x-4)^2)`
`=(-2x+4)/((x+1)(x-1)^2) . ((x-1)^2 . (x+1)^2)/((2x-4)^2)`
`= (-(2x-4))/((x+1)(x-1)^2) . ((x-1)^2 . (x+1)^2)/((2x-4)^2)`
`=-(x+1)/(2x-4)`
`=(-x-1)/(2x-4)`