Algebra 2 (1st Edition)

For all 3 solids, the volume is the product of their height, width and length. Thus for Solid I: $a\cdot a\cdot(a-b)=a^2(a-b)$. for Solid II: $a\cdot b\cdot(a-b)=ab(a-b)$. for Solid III: $b\cdot b\cdot(a-b)=b^2(a-b)$.