What is (9j+3)-(2j+6)

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%)

Rewrite the expression in z to the n power. the expression i was given is: 1 over z to the negative 1 half power.

How many degrees are there in the central angles in a circle