The next step is to identify which, if any, terms can be combined. Remember, only like terms — constant terms or terms with the same variable — can be combined.
x^3-2x^2+ 3x+1+x^4 -7x
In this case, we have two x-terms. Only the x-terms can be combined, so to simplify the expression we will rearrange it according to the Commutative Property of Addition and then evaluate the difference between the like terms.
