F(x) = ∫ 6x^2 dx = 6x^3/3 + C = 2x^3 + C
y = 2x^3 + C ==> K(x;y) = K(-1;4)
4 = 2(-1)^3 + C
4 = - 2 + C
C = 6
y = 2x^3 + 6
