Not an algebraic set

[Papapetros Vaggelis]

Let \(\displaystyle{\varnothing\subset V(I)\subset \mathbb{K}^n}\), where \(\displaystyle{I}\) is an

ideal of \(\displaystyle{\mathbb{K}[x_1,...,x_n]}\) and \(\displaystyle{\mathbb{K}}\) is an algebraically closed field.

Show that \(\displaystyle{\mathbb{K}^n-V(I)}\) is not an algebraic set.