To evaluate the expression $6x - y$ for $x = 10$ and $y = 3$, substitute the values of $x$ and $y$ into the expression:

$6(10) - 3 = 60 - 3 = 57$

So, the value of the expression is 57.

Do you want more details or have any questions?

Here are five related questions to further your understanding:

1. What is the value of $4x + 2y$ when $x = 10$ and $y = 3$?
2. How would the expression $6x - y$ change if $y$ were doubled?
3. What is the result of the expression $6x - y^2$ for $x = 10$ and $y = 3$?
4. How would you solve the equation $6x - y = 0$ for $y$ in terms of $x$?
5. What happens to the value of $6x - y$ if both $x$ and $y$ are increased by 1?

Tip: Always double-check your substitution and arithmetic steps to ensure accuracy in calculations.