Calculation of molar concentration of salt with known Ksp

I need some clear and simple help on understanding how to calculate the molar concentration of an ion if the Ksp of the compound is known:

I have 2 problems that I want to clearly understand:

1) Zinc hydroxide: --- if the Ksp for Zn(OH)2 is 1.2x10^-17 M and my solubility equation is: Ksp = [Zn] [OH]^2 --- how do I determine the concentration of the Zn??

2) Similarly, if I have zinc phosphate (Zn3(PO4)2 and I know the Ksp is 9.0x10-33 M, again how do I determine the molar concentration of the Zn when I have [Zn]^3 [PO4]2??

I really need to understand the math and how this works

Many thanks

Solution Summary

The solution is comprised of step-by-step examples of calculation of molar concentration of salts when their solubility product is given.