Could someone covert these for me?? thanks!!

Inez has a phone card. the graph shows the number of minutes that remain on her phone card a certain number of days.

Solve each quadratic equation by factoring and using the zero product property. n^2 - 49 = 0

Astudent must have an average on five test that is greater than it equal to 80% but less than 90% to receive a final grade of b. devon's greades on the first four test were 78% 62% 91% and 80% what range if grades on the fifth test would give him a b in the course? ( assuming the highest grade is 100%)