Answer:
[tex]3m+3n[/tex]
Step-by-step explanation:
The distributive property is defined as the multiplication of a number by a sum is equal to the sum of the multiplications of that number by each of the addends:
[tex](a+b)c=ac+bc[/tex]
Using the previous property:
[tex]3(m+n)=(3*m)+(3*n)=3m+3n[/tex]
