Calculate the hydroxide ion concentration of 0.15 M NH3 Ki = 1.8*10E-5?

Question

Most explanations of mathematical calculations for best answer please. Thank you.

Answer 1

1.8^10-5 = [NH4+][OH-]/[NH3] = x^2/(0.15-x)

x<<<0.15, so it can be ignored in the denominator

2.7 * 10^-6 = x^2
x = [OH-] = 0.00164 M

Answer 2

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