F (x) = x/2 + 2 x + 3 помогите решить

F (x) = 3+2x+x2

f (x+2) = 3+2 (x+2) + (x+2) 2

f (x-2) = 3+2 (x-2) + (x-2) 2

f (x+2) = f (x-2) + 4

3+2 (x+2) + (x+2) 2 = 3+2 (x-2) + (x-2) 2 + 4

2x+4+x2+4x+4 = 2x-4+x2-4x+4 + 4

4 = 2x+x2-4x - 2x - x2 - 4x

4 = - 8x

x = - 0.5

Проверим

f (-0,5+2) = 3+2 (1,5) + (1,5) 2 = 6 + 2,25 = 8,25

f (-0,5-2) = 3+2 (-2,5) + (-2,5) 2 = - 2 + 6,25 = 4,25

f (x+2) = f (x-2) + 4

8,25 = 4,25 + 4

Верно ...