The Ksp of Cu(OH)2 at 298 K is 1.60×10-19. Determine the molar solubility of this salt.

I'm unsure what i am doing incorrect.

I thought i had to do:

Ksp = (Cu^2+)(OH^-)2

Ksp = (x)(2x)2

Ksp = 4x3

x = 1.64E-56