The given expression is:

$5x + 2x^2 - 1 + 3x - 2y$

Let's simplify it by combining like terms:

1. Combine the terms involving $x$: $5x + 3x = 8x$

2. The term involving $x^2$ is $2x^2$, which stays as it is.

3. The constant term is $-1$.

4. The term involving $y$ is $-2y$.

Thus, the simplified expression is:

$2x^2 + 8x - 1 - 2y$

Would you like more details or have any further questions?

Here are five related questions for further practice:

1. What is the derivative of the expression with respect to $x$?
2. How would you factor $2x^2 + 8x$?
3. What happens if you set $x = 1$ and $y = 0$ in the expression?
4. How can you complete the square for the $x$ terms?
5. What is the result when you substitute $x = 2$ and $y = -1$?

Tip: Always start by combining like terms in expressions to simplify before further operations like factoring or solving.