It's an old topic, nothing new. First, f(x)=x 1, and f(x)=x2 is the solution of the equation. Then, combining with the number shape, we can easily get that there are two solutions for f(x)=x 1. With f(x 1)=x 1 as the focus of f(x) and y=x, we can draw in two categories, and it is easy to get the size relationship between f(x2) and x2, and get a solution of f(x)=x2.