Answer
$$-3x^3+2x^2-3x+4$$
Work Step by Step
Like terms must (1) be raised to the same power and (2) consist of the same variable (i.e. x and y are not like terms). It is also important to note that numbers are all like terms with each other when not multiplied by anything. Thus, combining like terms, we obtain:
$$-3x^3+2x^2-3x-3+7 \\ -3x^3+2x^2-3x+4$$
