A14-ounce box of cereal sells for $2.10. what is the unit rate?

What is the slope simplify your answer and write it as a proper fraction, improper fraction, or integer

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

[10 points, algebra 2]according to my answer key the restrictions are -1 and 4. but why not positive 1?