Respuesta :

The simplified expression are as follows;

6mn³ - mn² +  3mn³ + 15mn² =  9mn³ + 14mn²

a⁴b³ + 8a⁴b³  = 9a⁴b³

How to simplify an expression?

A simplified expression is express to its lowest term.

Therefore,

6mn³ - mn² +  3mn³ + 15mn²

combine like terms

6mn³  +  3mn³ - mn² + 15mn²

9mn³ + 14mn²

a⁴b³ + 8a⁴b³  = 9a⁴b³

learn more on simplification here: https://brainly.com/question/403991

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