Please help me! I need to get this done but don't know how!

The polynomial x³+5x²-57x-189 expresses the volume, in cubic inches, of a shipping box, and the width is (x+3) in. If the width of the box is 15 in., what are the other two dimensions?

a. height: 19 in.
depth: 5 in.

c. height: 19 in.
depth: 7 in.

b. height: 21 in.
depth: 5 in.

d. height: 21 in.
depth: 7 in.