The solution of fractional equation 5-x / x-4 + 1 / 4-x = 1 5-x and 1 are molecules, and x-4 and 4-x are denominators,

The solution of fractional equation 5-x / x-4 + 1 / 4-x = 1 5-x and 1 are molecules, and x-4 and 4-x are denominators,

(5-x)/(x-4) + 1/(4-x)=1
==>
(5-x)/(x-4) - 1/(x-4)=1
==>
(4-x)/(x-4) =1
==>
-1=1
Therefore, the original equation has no solution!