Which equation represents a direct variation?

Which is the graph of f(x) = (4)x? image for option 1 image for option 2 image for option 3 image for option 4

What is the distance between a and b? round your answer to the nearest tenth. a coordinate plane is shown. point a is located at negative 1, 5, and point b is located at 4, 1. a line segment connects the two points.

Arock was dropped from the top of a building. the function that describes the height after it was dropped is f(x)=64-16x^2. what are the zeros of the function and what do they mean?