Đáp án+Giải thích các bước giải:
`x/(2x-6)+x/(2x+2)=(2x)/[(x-3)(x+1)]` (`ĐK : x\ne-1;x\ne3`)
`<=> x/[2(x-3)]+x/[2(x+1)]=(2x)/[(x-3)(x+1)]`
`<=> [x(x+1)]/[2(x-3)(x+1)]+[x(x-3)]/[2(x-3)(x+1)]=[2.2x]/[2(x-3)(x+1)]`
`<=> x^2+x+x^2-3x=4x`
`<=> 2x^2-2x-4x=0`
`<=> 2x^2-6x=0`
`<=> 2x(x-3)=0`
`<=>`\(\left[ \begin{array}{l}2x=0\\x-3=0\end{array} \right.\)
`<=>`\(\left[ \begin{array}{l}x=0 (tm)\\x=3(ktm)\end{array} \right.\)
Vậy `S={0}`
