Answer :

Remember that

The volume of a cube is equal to

[tex]V=b^3[/tex]

where b is the long side of the cube

so

Part 19

we have that

[tex]b=7c^6d^2[/tex]

substitute in the formula

[tex]V=(7c^6d^2)^3[/tex]

Applying property of exponents

[tex]\begin{gathered} V=(7^3)(c^{(6\cdot3)})(d^{(2\cdot3)}) \\ V=342c^{(18)}d^6 \end{gathered}[/tex]

Part 20

we have

[tex]b=6r^7s^8[/tex]

substitute in the formula

[tex]\begin{gathered} V=(6r^7s^8)^3 \\ V=216r^{(21)}s^{(24)} \end{gathered}[/tex]