Respuesta :

Answer:

3m² + 2mn + 7n²

Step-by-step explanation:

Subtract m² + 3mn - n² from 4m² + 5mn + 6n², that is

4m² + 5mn + 6n² - (m² + 3mn - n²)

= 4m² + 5mn + 6n² - m² - 3mn + n² ← collect like terms

= 3m² + 2mn + 7n²