Answer:
3a+13b+2c
Explanation:
Like terms are terms with the same variable, which in this case is 5b and 8b.
Using the distributive property,
5b+8b=(5+8)b=13b
Since there are no other like terms, all you have to do is use 13b in the expression instead of 5b and 8b, and you end up with
3a+13b+2c
Hope this helps!