Answer
$$=x^5-2x$$
Work Step by Step
We simplify the expression by combining like terms. 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:
$$2x^5-x^4-x-x^5+x^4-x \\ =2x^5-x^4-x-x^5+x^4-x \\ =x^5-2x$$
