Line a passes through points (2, 1) and (7, 9). Line b is perpendicular to a. What is the slope of line b? Simplify your answer and write it as a proper fraction, improper fraction, or integer.

Two cars which are 40 miles apart start moving simultaneously in the same direction with constant speeds. if the speed of the car which is behind is 56 mph and the speed of the other car is 48 mph, how many hours will it take for the car which is behind to catch up the car ahead of it?

Can someone answer this question for me

What is the solution to the division problem below x3+x2-11x+4/x+4