Please help me solve the questions attached below

Determine whether the following statements are true and give an explanation or counterexample. bold a. when using the shell method, the axis of the cylindrical shells is parallel to the axis of revolution. bold b. if a region is revolved about the y-axis, then the shell method must be used. bold c. if a region is revolved about the x-axis, then in principle it is possible to use the disk/washer method and integrate with respect to x or the shell method and integrate with respect to y.

Spencer has 1/3 pound of nuts he divides them equally into 4 bags what fraction of a pound of nuts is in each bag

The equation of a parabola is given. y=18x2+4x+20 what are the coordinates of the focus of the parabola?