Đáp án:
`(5x+4)/(x^2+2x)+(3x)/(x+2)=2/x` ĐKXĐ: `x\ne0;x\ne-2`
`<=>(5x+4)/(x(x+2))+(3x)/(x+2)=2/x`
`<=>(5x+4+3x.x)/(x(x+2))=(2.(x+2))/(x(x+2))`
`=>5x+4+3x^2=2x+4`
`<=>3x^2+5x-2x+4-4=0`
`<=>3x^2+3x=0`
`<=>3x(x+1)=0`
`<=>` \(\left[ \begin{array}{l}3x=0\\x+1=0\end{array} \right.\) `<=>` \(\left[ \begin{array}{l}x=0(\text{ktmđk})\\x=-1(\text{tmđk})\end{array} \right.\)
Vậy `S={-1}`
