Does the oval graph represent a function why or why not?

Use the method of cylindrical shells to find the volume v generated by rotating the region bounded by the curves about the given axis.y = 7ex, y = 7e^-x, x = 1; about the y-axis

Which of the following is the graph of y= square root -x-3

If x varies directly as y, and x = 7.5 when y = 10, find x when y = 4