SOLUTION: if m^2 + n^2 = 18 and mn = 7, what is (m-n)^2?

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Question 1101321: if m^2 + n^2 = 18 and mn = 7, what is (m-n)^2?
Answer by ikleyn(52848) About Me  (Show Source):
You can put this solution on YOUR website!
.
%28m-n%29%5E2 = m%5E2+-+2mn+%2B+n%5E2 = %28m%5E2%2Bn%5E2%29 - 2mn = 18 - 2*7 = 4.

Answer. 4.