Write Expression from Context (Ax+By)

Simplify the given expression leaving the answer in improper fraction form. 2/3+5/6

Choose the right classification of 5x + 3x^4 - 7x^3 + 10 by number terms and he degree 1. third degree polynomial 2. fourth degree polynomial 3. sixth degree polynomial 4. first degree binomial

Atourist boat is used for sightseeing in a nearby river. the boat travels 2.4 miles downstream and in the same amount of time, it travels 1.8 miles upstream. if the boat travels at an average speed of 21 miles per hour in the still water, find the current of the river.