To simplify the expression $2x - 3y + 5z - 2x + 4y - 6z$, combine the like terms for each variable ($x$, $y$, and $z$):

1. Combine $x$ terms: $2x - 2x = 0$

2. Combine $y$ terms: $-3y + 4y = y$

3. Combine $z$ terms: $5z - 6z = -z$

Putting it all together, the simplified expression is: $y - z$

Would you like additional steps or have any questions?

Here are some related questions to consider:

1. How would you simplify an expression with more variables?
2. How can you solve an equation that contains terms similar to this one?
3. What is the importance of identifying like terms in algebraic expressions?
4. How would you simplify if there were coefficients in front of each term with variables?
5. What role do parentheses play in expressions with terms like these?

Tip: Always look for like terms first when simplifying an expression—it often saves time and simplifies the process.