Решите уравнение f(x-1)+f(x+1)=x² , если f(x)=2x+x²-1

(2x+x²-1 -1) + (2x+x²-1 +1) = x^2

x^2 +2x -2 +x^2 +2x -x^2 = 0

x^2 +4x -2 = 0

D = 16 +8 = 24

x = (-4 -√24) / 2 = -2 -√(24/2²) = -2 -√6
x = (-4 -√24) / 2 = -2 +√(24/2²) = 2+√6