A) let f(x) = x + |2x − 5|. find all solutions to the equation f(x) = 4. (enter your answers as a comma-separated list. if an answer does not exist, enter dne.)

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%)