The volume of a prism is the product of the area of a the base and its height. Given the volume of the prism as 15x2 + x + 2 and the height as x2, the base can be expressed using this expressions. Volume = base x height. By substitution, 15x2 + x + 2 = (base) x (x2). Thus the answer is, base = (15x2 + x + 2)/x2 or base = 15 + (1/x) + (2/x2).