What is 5x-4 2x-8?

The expression 5x - 4 2x - 8 is not written correctly, as there is no operation between the terms 5x - 4 and 2x - 8. It seems like there might be a missing operator, such as a plus or minus sign, between the two terms. Without knowing the intended operation, it is not possible to simplify or evaluate the expression accurately.