The area of cardboard she used is given by the formula A =
, where s represents the side length of the cube.
Now the question asks for the equation , which we can use to solve for s
it means
we have to solve for s
or in other words we have to isolate s
Now
A=

Divide both sides by 6

or

Take square root on both side

So this is the formula we can use to solve for s