I cannot figure this one out 12x+13y(12+6). Please help!

I am not a teacher but this is how I would go about it :)

12x + 13y(12+6)
=12x + 13y(18)
=12x + 234y
=6(2x + 39y)

You firstly add what is in the bracket and then multiply it by what stands in fron of the bracket. Then you can take the common factor in front of the bracket just to make it look nicer ;)
Hope it helps =)