3 2 + 3*x - x
2 + 3*x - x^3 при x = 1/3
2 + 3*x - x^3
2 + 3*(1/3) - (1/3)^3
2 + 3/3 - (1/3)^3
80/27
2.0 - x^3 + 3.0*x
2 -(1 + x) *(-2 + x)