Let's simplify the expression $(3mn + 2n^2 − 3m^2) + (4m^2 − 2n^2 + 6mn)$.

1. Group like terms: $(3mn + 6mn) + (2n^2 - 2n^2) + (-3m^2 + 4m^2)$

2. Simplify each group:

   • $3mn + 6mn = 9mn$
   • $2n^2 - 2n^2 = 0$
   • $-3m^2 + 4m^2 = m^2$

3. Combine the simplified terms: $9mn + m^2$

So, the simplified expression is:

$m^2 + 9mn$

Would you like more details or have any questions?

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Related Questions:

1. How would you factor the expression $m^2 + 9mn$?
2. What if the expression had a subtraction sign between the two groups instead of addition?
3. Can you expand and simplify $(m + 3n)(m + 3n)$?
4. How does the distributive property apply in simplifying expressions like this?
5. What happens if one of the variables in the expression equals zero?

Tip: When simplifying expressions, always combine like terms, which are terms with the same variables raised to the same power.