There are two explanations for the square of mn in the title.

1, the square of mn is the square of (mn), then

The square of mn-(n-1) = the square of1-(n- 1)= 1-n+1= 2-n.

2. the square of 2.mn means m * (the square of n), then

The square of mn-(n- 1) = m * n * n-(n-1) =1* n-(n-1) = n-n+1=/kloc-.

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