Find the missing side length.

2x minus y equals 6, x plus y equals negative 3

The value of cos 30° is the same as which of the following?

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%)