Answer:
The simplified form of the expression 12m²n + 3mn is 3mn(4m + 1).
Explanation:
To simplify the expression 12m²n + 3mn, we can factor out the common term "mn" from both terms:
12m²n + 3mn = mn(12m + 3)
Now, we can simplify further by factoring out 3 from the parentheses:
mn(12m + 3) = 3mn(4m + 1)