If the quadratic functions f 1 (x) and F 2 (x) satisfy the following conditions: (1) f (x) = f 1 (x) + F 2 (x) monotonically decreases on R; (2) g (x) = f 1 (x) - F 2 (x) pairs (2) For any real number x1, X2 (x1 ≠ x2), if G (x1) + G (x2) / 2 > G (x1 + x2 / 2), then F1 (x) = F2 (x)=

If the quadratic functions f 1 (x) and F 2 (x) satisfy the following conditions: (1) f (x) = f 1 (x) + F 2 (x) monotonically decreases on R; (2) g (x) = f 1 (x) - F 2 (x) pairs (2) For any real number x1, X2 (x1 ≠ x2), if G (x1) + G (x2) / 2 > G (x1 + x2 / 2), then F1 (x) = F2 (x)=

There are too many such functions. I'll give you an example
f1(x)=x^2-x,f2(x)=-x^2-x