Giải thích các bước giải:
a.$\dfrac{x-28}{1990}+\dfrac{x-32}{1986}+\dfrac{x-10}{1004}=4$
$\to (\dfrac{x-28}{1990}-1)+(\dfrac{x-32}{1986}-1)+(\dfrac{x-10}{1004}-2)=0$
$\to\dfrac{x-28-1990}{1990}+\dfrac{x-32-1986}{1986}+\dfrac{x-10-2.1004}{2.1004}=0$
$\to\dfrac{x-2018}{1990}+\dfrac{x-2018}{1986}+\dfrac{x-2018}{2.1004}=0$
$\to(x-2018)(\dfrac{1}{1990}+\dfrac{1}{1986}+\dfrac{1}{2.1004})=0$
$\to x=2018$
b.$\dfrac{x-1932}{86}+\dfrac{x-1850}{84}+\dfrac{x-1772}{82}=6$
$\to (\dfrac{x-1932}{86}-1)+(\dfrac{x-1850}{84}-2)+(\dfrac{x-1772}{82}-3)=0$
$\to \dfrac{x-2018}{86}+\dfrac{x-2018}{84}+\dfrac{x-2018}{82}=0$
$\to (x-2018)(\dfrac{1}{86}+\dfrac{1}{84}+\dfrac{1}{82})=0$
$\to x=2018$
