Please help me ASAP please and thank you

Write an equation for the function that includes the points (2,100)and (3,100)

For f(x) = 3x+1 and g(x) = x2 - 6, find (g/f)(x)

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%)