1.(A- 1)( 1/A- 1- 1/A+A+ 1/ 1-A)=(A- 1)[(A+A+ 1)-(A- 1)- 1]/(A- 1) = A+ 1AX-B = 2x-3 to at least two roots, the solution is x=(b-3)/(a-2), and there is only one root at this time, a≠2. If condition a=2, b = 3 ... y =-14. X=3 when m= 1. When m is not equal to 1, this equation is a quadratic equation, and the discriminant △ = (2m-1)+12 (m-1). That is, when-(root number 15)/2- 1 < m