What is -9+n/4=-7? explain in detail, i don’t really understand this at all.

The size of a certain cell is 2.5*10^-9m. another cell is 1.5*10^3 times larger. how large is the larger cell in scientific notation?

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%)

Astraight water slide is 175 feet above ground and is 200 feet long. what is the angle of depression to the bottom of the slide?