Having trouble simplifying terms. the equation is n4+n3+3n-n-n3? how dou you simplify this term?

What is the measure of the smallest angle in the diagram? 15 29 32 45

Astick 2 m long is placed vertically at point b. the top of the stick is in line with the top of a tree as seen from point a, which is 3 m from the stick and 30 m from the tree. how tall is the tree?

Roger could feed 5 walruses with 4 kilograms of fish. how many walruses could he feed with 7.2 kilograms of fish?