The polynomial to be added to –7mn + 2m² + 3n² to obtain 5m² + 2mn - 9n² is: 3m² - 11n² + 9mn.
<h3>Addition of Polynomials</h3>
Like terms should be combined together when adding polynomials.
Let x represent the polynomial expression that would be added to –7mn + 2m² + 3n² to obtain 5m² + 2mn - 9n².
Therefore:
–7mn + 2m² + 3n² + x = 5m² + 2mn - 9n².
x = 5m² + 2mn - 9n² - (-7mn + 2m² + 3n²)
x = 5m² + 2mn - 9n² + 7mn - 2m² - 3n²
Combine like terms together.
x = 3m² - 11n² + 9mn
Therefore, the polynomial to be added to –7mn + 2m² + 3n² to obtain 5m² + 2mn - 9n² is: 3m² - 11n² + 9mn.
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