要是解X的话(m^2-1)x-m^2+m+2=0 x = (m^2 -m -2)/(m^2-1) = 1 - (m+1)/(m^2 - 1) = 1 - 1/(m-1) = (m-2)/(m-1)
(m+1)(m-1)x-(m-2)(m+1)(m+1)(mx-x-m+2)
