What is the difference between 5 cu ft and 5.0 cu ft

Question and answers are in the attached picture. you so much in advance.

Draw a tape diagram to represent each situation.for some of the situations,you need to decide what to represent with a variable andre bakes 9 pans of brownies.he donates 7 pans to the school bake sale and keeps the rest to divide equally among his class of 30 students

If x = -2, then x 2-7x+10 equals a. 0 b.20 c.28