The expression $5x - 2x$ can be simplified by combining like terms.

$5x - 2x = (5 - 2)x = 3x$

So, the simplified expression is $3x$.

Do you want more details or have any questions? Here are some related questions:

1. How would you simplify the expression $7y - 3y + 2y$?
2. What is the result of combining like terms in the expression $4a + 3a - 2a$?
3. Can you simplify the expression $10x - 5x + 2x$?
4. How would you simplify the expression $8m - 3m + m$?
5. What happens when you combine the terms $6p + 4p - p$?

Tip: Always look for like terms to simplify algebraic expressions efficiently.