Let's simplify the given expression:

$(5x - 2 + 3x^2) + (4x + 3)$

Step-by-step solution:

1. Remove parentheses (since we're adding the terms, they remain unchanged): $5x - 2 + 3x^2 + 4x + 3$
2. Combine like terms:
   • Combine $x^2$ terms: There's only $3x^2$, so it remains.
   • Combine $x$ terms: $5x + 4x = 9x$.
   • Combine constant terms: $-2 + 3 = 1$.

Thus, the simplified expression is: $3x^2 + 9x + 1$

The correct answer is: $3x^2 + 9x + 1$.

Would you like further details or explanations?

Here are 5 questions to expand on this concept:

1. How do you identify like terms in an expression?
2. What happens when you subtract polynomials instead of adding them?
3. How would you simplify if the expression involved a negative sign between the terms?
4. How do higher-degree terms (e.g., $x^3$ or $x^4$) affect the simplification process?
5. Can you simplify the expression if variables with different powers appear in it?

Tip: Always arrange terms in descending order of their powers (e.g., $x^2, x, \text{constant}$) to maintain a standard form!