已知f(2x+1)=x^2-2x，求f(x)与f(2x-1)的解析式

f(2x+1)=x^2-2x =(4x^2+4x+1)/4-3x-1/4 =(2x+1)^2/4-(2x+1)*3/2+5/4 所以， f(x)=x^2/4-3x/2+5/4 f(2x-1)=(2x-1)^2/4-3(2x-1)/2+5/4 =(4x^2-4x+1)/4-(6x-3)/2+5/4 =x^2-4x+3