Let f (x) = - x square + 2aX + a square satisfy f (2) = f (a)

Let f (x) = - x square + 2aX + a square satisfy f (2) = f (a)

Because f (2) = f (a)
So - 4 + 4A + A ^ 2 = - A ^ 2 + 2A ^ 2 + A ^ 2, the solution is a = 2
Substituting into the original formula: F (x) = - x ^ 2 + 4x + 4, after deformation, f (x) = - (X-2) ^ 2 + 8, the vertex of the function is x = 2, y = 8, which is the maximum value of the function