What is the initial value of the linear function through a and b a (4,9) b (-8,-9)

Shane can shovel the driveway in 4 hours, but if his sister it would take 2 hours. how long would it take taylor to shovel the driveway alone

Which of these tables represents a non-linear function?

Acyclist bike x distance at 10 miles per hour .and returns over the same path at 8 miles per hour.what is the cyclist average rate for the round trip in miles per hour ?