The expression $3x + 5 - 2x + 7$ can be simplified by combining like terms:

• Combine the $x$-terms: $3x - 2x = x$
• Combine the constants: $5 + 7 = 12$

Thus, the simplified expression is: $x + 12$

Would you like more details or have any questions?

Here are 5 related questions to expand on this concept:

1. How do you simplify expressions with multiple variables?
2. What happens when there are negative coefficients in an expression?
3. How can you solve for $x$ if this expression is set equal to a number?
4. How do you factor expressions like this one?
5. What is the distributive property, and how does it apply to expressions?

Tip: Always combine like terms first when simplifying expressions to make calculations easier!