Đáp án:
Giải thích các bước giải:
`\frac{x+1}{99}+\frac{x+2}{98}=\frac{x+3}{97}+\frac{x+4}{96}`
`⇔ \frac{x+1}{99}+1+\frac{x+2}{98}+1=\frac{x+3}{97}+1+\frac{x+4}{96}+1`
`⇔ \frac{x+100}{99}+\frac{x+100}{98}=\frac{x+100}{97}+\frac{x+100}{96}`
`⇔ (x+100)(\frac{1}{99}+\frac{1}{98})=(x+100)(\frac{1}{97}+\frac{1}{96)`
`⇔ (x+100)(\frac{1}{99}+\frac{1}{98}-\frac{1}{97}-\frac{1}{96})=0`
`⇔ x+100=0`
`⇔ x=-100`
Vậy `S={-100}`
