1x3+3x5+5x7+7x9+.+27x29的结果是什么数
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1x3+3x5+5x7+7x9+.+27x29
=(1x3x(5-(-1))+3x5 x(7-1)+5x7 x(9-3)+7x9 x(11-5)+.+27x29
x(31-25))x1/6
=(1x3x5-(-1x1x3)+3x5x7-1x3x5+5x7x9-3x5x7+7x9x11-5x7x9+.+27x29x31-25x27x29))x1/6
=(25x27x29-(-1x1x3))x1/6
=(19575+3)x1/6
=3263
=(1x3x(5-(-1))+3x5 x(7-1)+5x7 x(9-3)+7x9 x(11-5)+.+27x29
x(31-25))x1/6
=(1x3x5-(-1x1x3)+3x5x7-1x3x5+5x7x9-3x5x7+7x9x11-5x7x9+.+27x29x31-25x27x29))x1/6
=(25x27x29-(-1x1x3))x1/6
=(19575+3)x1/6
=3263
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