Hướng dẫn trả lời:
`x/2016 + {x+1}/2017 + {x+2}/2018 + {x+3}/2019 + {x+4}/2020 = 5`
`↔ x/2016 + {x+1}/2017 + {x+2}/2018 + {x+3}/2019 + {x+4}/2020 - 5 = 0`
`↔ (x/2016 - 1) + ({x+1}/2017 - 1) + ({x+2}/2018 - 1) + ({x+3}/2019 - 1) + ({x+4}/2020 - 1) = 0`
`↔ (x/2016 - 2016/2016) + ({x+1}/2017 - 2017/2017) + ({x+2}/2018 - 2018/2018) + ({x+3}/2019 - 2019/2019) + ({x+4}/2020 - 2020/2020) = 0`
`↔ {x - 2016}/2016 + {x + 1 - 2017}/2017 + {x + 2 - 2018}/2018 + {x + 3 - 2019}/2019 + {x + 4 - 2020}/2020 = 0`
`↔ {x - 2016}/2016 + {x - 2016}/2017 + {x - 2016}/2018 + {x - 2016}/2019 + {x - 2016}/2020 = 0`
`↔ (x - 2016)cdot(1/2016 + 1/2017 + 1/2018 + 1/2019 + 1/2020) = 0`
Vì `1/2016 + 1/2017 + 1/2018 + 1/2019 + 1/2020 > 0` nên:
`↔ x - 2016 = 0`
`↔ x = 2016`
Vậy `x = 2016`
Đáp án:
`x = 2016`
