There is no solution to the fractional equation, that is to say, the value of x makes the common denominator zero, which can make the whole equation after denominating, so we can substitute the value that makes the common denominator zero into the whole equation after denominating and find the value of unknown letters. For example, the equation about X is (a- 1)/(X+2) +3=2x/(x+2), which can be solved as follows: the denominator of the original equation is: a- 1+3(x+2)=2x, and X =-.