To simplify the given expression $3(y - 6) - 5y$, follow these steps:

1. Distribute the $3$ to both terms inside the parentheses: $3(y - 6) = 3y - 18$

   So, the expression becomes: $3y - 18 - 5y$

2. Combine like terms ($3y$ and $-5y$): $3y - 5y = -2y$

   Now the expression is: $-2y - 18$

3. The simplified expression is: $-2y - 18$

Let me know if you need further clarification or have any questions! Here are some related questions for practice:

1. How do you simplify $2(3x + 4) - 7x$?
2. What is the result of distributing $-4$ in ( -4(a + 5)