Giải thích các bước giải:
`(1/1.2+1/2.3+1/3.4+....+1/999.1000).(1/2+1/3+1/4+1/5+1/6+...+1/100).(3x+3)=(2/1.3+2/[3.
5]+...+2/99.101).(2^4-4^2. 999!).100!.(123456789/23456789)`
`(1/1.2+1/2.3+1/3.4+....+1/999.1000).(1/2+1/3+1/4+1/5+1/6+...+1/100).(3x+3)=(2/1.3+2/[3.
5]+...+2/99.101).(16-16. 999!).100!.(123456789/23456789)`
`(1/1.2+1/2.3+1/3.4+....+1/999.1000).(1/2+1/3+1/4+1/5+1/6+...+1/100).(3x+3)=(2/1.3+2/[3.
5]+...+2/99.101).(0. 999!).100!.(123456789/23456789)`
`(1/1.2+1/2.3+1/3.4+....+1/999.1000).(1/2+1/3+1/4+1/5+1/6+...+1/100).(3x+3)=(2/1.3+2/[3.
5]+...+2/99.101).0.100!.(123456789/23456789)`
`(1/1.2+1/2.3+1/3.4+....+1/999.1000).(1/2+1/3+1/4+1/5+1/6+...+1/100).(3x+3)=0`
`=>`+ `1/1.2+1/2.3+1/3.4+....+1/999.1000=0(1)`
+`1/2+1/3+1/4+1/5+1/6+...+1/100=0(2)`
+`3x+3=0(3)`
Nhìn vào đẳng thức,hiển nhiên ta thấy `(1),(3)` vô lý vì 2 phép tính đó luôn `!=0`
`=>(3)=0`
`=>3x+3=0`
`=>3x=0-3`
`=>3x=(-3)`
`=>x=(-3):3`
`=>x=(-1)`
Vậy `x=(-1)`
