Đáp án:
`S={1/9}`
Giải thích các bước giải:
`d)(x³-(x-1)³)/[(4x+3)(x-5)]=(7x-1)/(4x+3)-x/(x-5)(ĐKXĐ:x`$\neq$ `5,x`$\neq$ `-3/4)`
`⇔(x³-(x-1)³)/[(4x+3)(x-5)]=[(7x-1)(x-5)]/[(4x+3)(x-5)]-[x(4x+3)]/[(4x+3)(x-5)]`
`⇒x³-(x-1)³=(7x-1)(x-5)-x(4x+3)`
`⇔x³-(x³-3x²+3x-1)=7x²-35x-x+5-4x²-3x`
`⇔x³-x³+3x²-3x+1=(7x²-4x²)-(35x+x+3x)+5`
`⇔3x²-3x+1=3x²-39x+5`
`⇔3x²-3x-3x²+39x=5-1`
`⇔36x=4`
`⇔x=4/36`
`⇔x=1/9(TM` `ĐKXĐ)`
Vậy `S={1/9}`
