An open topped rectangular box with a square base is to be constructed with a volume of . Find the Dimension that require the lease amount of surface material.

and...

In microcomputers, most of the components are squeezed into a single box-shaped block. If the block has a length equal to twice the width and if the total surface area of the block must be in order to dissipate the heat produced, find the dimensions for the maximum volume of the block.

I couldn't figure out how to get equations out of these two problems.

Thanks.