C equals ky cubed divided by Q. solve for Q

Although I can't tell you everything I'll help you get started.

Multiply both sides by Q, getting:
CQ=ky^3

Now you're just one more step to the answer.

You need to know that you can do any of the operations like add, subtract, multiply and divide to make Q alone. But remember that for each operation you make on one side, you have to do the same thing on the other side of the equal sign. Post your answer. :)