The expression w3 + w2 - w is not a valid mathematical expression, as the letter "W" cannot be used as a variable in algebraic expressions.
In algebra, letters are typically used to represent variables or unknown quantities.
In order to perform operations on an expression involving variables, we need to know the values of the variables or be given some information about their relationships. If we don't have any information about the values of the variables, we can still simplify some expressions by combining like terms or using algebraic rules, but the expression w3 + w2 - w cannot be simplified in this way because the letter "w" has no mathematical meaning in this context.