The given expression is:

$x + 3x - 3 + 2x^2 + 8 - 5x$

Let's simplify this step by step:

1. Combine like terms:
   • For the $x$ terms: $x + 3x - 5x = -x$
   • Constants: $-3 + 8 = 5$
   • The quadratic term $2x^2$ remains as it is.

So the simplified expression is:

$2x^2 - x + 5$

Would you like further details on this simplification or any other questions?

Here are 5 related questions to consider:

1. How do you factor quadratic expressions like $2x^2 - x + 5$?
2. What are the properties of quadratic equations in general?
3. How do you solve quadratic equations using the quadratic formula?
4. How do you complete the square for quadratic expressions?
5. What are some methods for graphing quadratic functions?

Tip: When simplifying algebraic expressions, always group similar terms like variables and constants to make the process easier.