Little help please?? Just figure out the slope and how to put it in y=mx+b form pls

Two cyclists 84 miles apart start riding toward each other at the samen time. one cycles 2 times as fast as the other. if they meet 4 hours later what is the speed (in miles) of the faster cyclists

Solve each quadratic equation by factoring and using the zero product property. n^2 - 49 = 0

Varies inversely with x. if y=8.5 when x=-1 find x when y=-1