F(x)=ax^2+bx+c ①F(x+2)=f(2-x) → a(x+2)^2+b(x+2)+c=a(2-x)^2+b(2-x)+c → 8a+2b=0 → b=-4a; ②图象过点(0,3), → F(0)=3 → c=3; ③ax^2-4ax+3=0的解x1、x2,满足(x1)^2+(x2)^2=10 → (x1+x2)^2-2*x1*x2=10 → (4a/a)^2-2*(3/a)=10 → a=1. F(x)=x^2-4x+3.