Please help!!! Banking

You call the pizza store and find out that eachpizza has 12 slices. you expect 16 people tocome, and you estimate each person will eat 3slices. how many pizzas should you order

The angle of a triangle are given as 6x,(x-3), and (3x+7). find x then find the measures of the angles

Any is very appreciated! (picture is provided below)not sure how to do this at all won't lie