(1)令t=(x-1)/(x+1)得：x=(t+1)/(1-t)∴f(t)=f{(x-1)/(x+1)}=2x-1=2(t+1)/(1-t)-1=(3t+1)/(1-t)即：f(t)=(3t+1)/(1-t)而把上式中所有的t换成x,等式依然成立∴f(x)=(3x+1)/(1-x)(2)f(x)=x²+(p-5)x-p+4=(x+p-4)(x...