Credit Repair Help

You have a square birthday cake that is 10″by 10″by 2″ deep. The cake is frosted on the top and sides. You plan to share the cake among five people (including yourself). How can you divide the cake so that each person gets exactly the same amount of frosting?

Please explain your answer. And just so you know my teacher doesn’t consider this cheating as long as I give your brilliance credit, so make sure to leave your name =]

Thanks!

If the sum of two numbers is 1 and the sum of the cubes of the numbers is 3, what is the sum of the squares of the numbers? (fractional answer, no decimals)

So I made two equations.

a+b=1
a^3+b^3=3

I have tried substitution and everything and I cannot get it.