A cheetauh running 90 feet per second is 100 feet behind Gazelle running 70 feet per second. How long will it take the cheetah to catch up to the gazelle?Write and solve a linear eguation. and how do you do multi step equations 24-6r=6(4-r) please explain

The relative velocity is what is important. Cheeta is going 20f/s faster than gazelle, and has to make up a distance of 100 ft.

distance=relativevelcotiy*time

On the multistep...you need to post a specific problem.