Question

use the solubility product for Fe(OH)3 to calculate the pH at which Fe(OH)3 begins to precipitate from a 0.20 M Fe^3+ solution

Answer 1

..........Fe(OH)3 -->Fe^3+ + 3OH^-

Ksp = (Fe^3+))OH^-)^3
You know Ksp (or can look it up)
(Fe^3+) = 0.2M from the problem.
Substitute and solve for OH^-, then convert to pH.