Austin is going for a run. He takes 4 hours to run 25.6 miles. What is his speed

Find the solution of this system of equation -7x+y=-20 9x-3y=36

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%)

Which of these angles are complementary? a. 45o and 45o b. 63o and 117o c. 45o and 135o d. 90o and 45o