Distribute the negative sign in the second half of the expression by multiplying that half by a -1. this should change the signs on all the numbers. this should leave you with the addition problem: (3x^2-x^3) + (5x^3 -2x^2 -1).
combine like terms by adding. -x^3 can be combined with 5x^3, but remember to follow their signs. this will give you 4x^3. the same can be done with 3x^2 and -2x^2, following their sign rules. this results in: x^2.
the negative one constant does not have any like terms, so he's by himself at the end of your new equation.
be sure to arrange your terms in decreasing order according to exponent, which results in your final answer.
