a) Assuming the problem statement means the edge length of the cubical case is 3w, three times the width of the artifact, the volume of the case is ...
V = s³ . . . . . . volume of a cube with edge length s
V = (3w)³
b) The expression can be simplified by applying the rules of exponents, distributing the exponent to the contents of parentheses.
V = 3³w³
V = 27w³