2 câu trả lời
$\dfrac{x}{2016}$`-`$\dfrac{1}{1010}$`=`$\dfrac{x+1}{2020}$`-`$\dfrac{1}{672}$
$\dfrac{x}{2016}$`+`$\dfrac{1}{672}$`=`$\dfrac{x+1}{2020}$`+`$\dfrac{1}{1010}$
$\dfrac{x}{2016}$`+`$\dfrac{3}{2016}$`=`$\dfrac{x+1}{2020}$`+`$\dfrac{2}{2020}$
$\dfrac{x+3}{2016}$`=`$\dfrac{x+3}{2020}$
`⇔` `x+3=0`
`x=-3`
Vậy `x=-3`
Đáp án:
`x/2016 - 1/1010 = ( x + 1 )/2020 - 1/672`
`->` `x/2016 - 1/1010 - ( x + 1 )/2020 + 1/672 = 0`
`->` `( x/2016 + 1/672 ) - ( 1/1010 + ( x + 1 )/2020 ) = 0`
`->` `( x/2016 + 3/2016 ) - ( 2/2020 + ( x + 1 )/2020 ) = 0`
`->` `( x + 3 ) / 2016 - ( x + 3 ) / 2020 = 0`
`->` `( x + 3 ) ( 1/2016 - 1/2020 ) = 0`
Mà `1/2016 - 1/2020 > 0`
`->` `x + 3 = 0`
`->` `x = -3`
Vậy `x = -3`.
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