Is 6z-15 is greater than or less than 4z+11 solvable?

In the pendulum formula t=2pi. read the problem on the picture ! ; $; $; ! ; ! ; ! ; )$; ! ; ! ; ! ; $; $; $! ; ! ; ); $; $$

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%)

Acable company claims that the average household pays $78 a month for a basic cable plan, but it could differ by as much as $20. write an absolute value inequality to determine the range of basic cable plan costs with this cable company. a. |x − 78| ≥ 20 b. |x − 20| ≥ 78 c. |x − 20| ≤ 78 d. |x − 78| ≤ 20