It is known that three mutually unequal rational numbers can be expressed in the form of 1a+ba and in the form of bb of 0a, while x
The second group has a 0, so in the first group, either a+b=0 or a=0. But in the second group, there are b/a and A in the denominator, so A is not equal to 0. So a+b=0, then a=-b, b/a=- 1. So the first group is 1, 0, a; The second group is 0,-1, B. Therefore, a=- 1 and b= 1. So the original formula =0+(- 1)-( 1)+4=2.