Just substitute the formula. M2-2M=N2-2N

Get (M-N)*(M+N-2)=0。

Because m is not equal to n.

M+N-2=0

So M+N=2.

So there is m = 2-n.

Use 2-N to return m in M*N, and bring N2-2N= 1 to get the answer.