Properties of Indefinite Integrals

Consider the following statements regarding the integration of the function $$4x^2+8x$$.

I. The indefinite integral $$\int (4x^2+8x) \,dx$$ evaluates to $$\frac{4x^3}{3}+ 4x^2+ C$$.

II. The derivative of $$\frac{4x^3}{3}+ 4x^2+ C$$ with respect to $$x$$ is $$4x^2+8x$$.

III. The expression $$4x^2+8x$$ can be factored as $$4x(x+2)$$. Applying an appropriate substitution to this factored form will result in an antiderivative that differs from the one in statement I by only a constant.

Which of the statements above are true?