You take the first term in the first bracket and multiply it by the second bracket
so that is 7x times by (4x+5)
then you take the second term +3 and multiply it by the second bracket.
If there were more terms would keep doing this but there are no more terms here.
So we have
now you just have to multiply out these brackets and then collect up the like terms.
You do it and I will check you working :)