Let any point x0 on f(x) and a point symmetric with respect to x= 1 on g(x) be X, then: (x0+x)/2= 1.

So x0=2-x, because x0 is on f(x), substituting f(x) has.

g(x)=f(x0)=f(2-x)=2(2-x)？ +2(2-x)+ 1, reduced to g(x)=2x? - 10x+ 13