$\text{Giải thích các bước giải:}$
$\dfrac{x+1}{2020} - \dfrac{x+2}{2019} = \dfrac{x+3}{2018} + 1$
$⇒ \dfrac{x+1}{2020} + 1 - \dfrac{x+2}{2019} - 1 = \dfrac{x+3}{2018} + 1$
$⇒ (\dfrac{x+1}{2020} + 1) - (\dfrac{x+2}{2019} + 1) = \dfrac{x+3}{2018} + 1$
$⇒ \dfrac{x+1+2020}{2020} - \dfrac{x+2+2019}{2019} = \dfrac{x+3+2018}{2018}$
$⇒ \dfrac{x+2021}{2020} - \dfrac{x+2021}{2019} = \dfrac{x+2021}{2018}$
$⇒ \dfrac{x+2021}{2020} - \dfrac{x+2021}{2019} - \dfrac{x+2021}{2018}= 0$
$⇒ (x + 2021)(\dfrac{1}{2020} - \dfrac{1}{2019} - \dfrac{1}{2018}) = 0$
$⇒ x + 2021 = 0$ $(\dfrac{1}{2020} - \dfrac{1}{2019} - \dfrac{1}{2018} \neq 0)$
$⇒ x = -2021$
$\text{Vậy x = -2021}$
$\text{Chúc bạn học tốt !}$
