狼0223 wrote:快手熊過程呢 設左上為 X...右上即為 8 - X...左下即為 13 - X...右下整合上述式子...(13-X) - 6 = 8 - (8 - X)13 - X - 6 = 8 - 8 + X7 = 2XX = 3.5其它的帶入即可...