a regular game board is composed of identical squares arranged in a rectangular array of r rows and r+1 columns. The r rows are numbered from 1 through r, abd the r+1 columns are numbered fro 1 through r+1. If r>10, which of the following represents the number of square s on the board that are neither in the 4th row nor in the 7th column a r2-r b r2-1 c r2 d r2+1 e r2+r
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发表于 2012-4-14 10:15:31
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