Copper (i) ions in aqueous solution react with nh3 (aq) according to

The complete question is; copper (i) ions in aqueous solutions react with NH3 (aq) according to;

Cu + 2NH3 = Cu (NH3) 2 Kt = 6.3 * 10^10

Calculate K

Cu + 2NH3 = Cu (NH3) 2

kf = 6.3 * 10^10

The ksp for CuBr = Cu + Br = 6.3 * 10^-9

For the reaction; CuBr + 2NH3 = Cu (NH3) 2 + Br to calculate K?

K = (6.3 * 10^10) (6.3*10^-9)

Thus K is 396.9