Final answer:
To simplify the expression 3 + 5x - 4 - 7x, combine like terms. The simplified expression is -1 - 2x.
Step-by-step explanation:
To simplify the expression 3 + 5x - 4 - 7x, we can combine like terms. 3 and -4 are constants, so we can combine them to get -1. 5x and -7x are terms with the same variable, so we can combine them to get -2x. Therefore, the simplified expression is -1 - 2x.