(1)36(x+y)二次-49(x-y)二次(2)(x+y)二次/4-(x-y)二次/4

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(1)36(x+y)二次-49(x-y)二次(2)(x+y)二次/4-(x-y)二次/4(1)36(x+y)二次-49(x-y)二次(2)(x+y)二次/4-(x-y)二次/4(1)36(x+y)二次

(1)36(x+y)二次-49(x-y)二次(2)(x+y)二次/4-(x-y)二次/4
(1)36(x+y)二次-49(x-y)二次(2)(x+y)二次/4-(x-y)二次/4

(1)36(x+y)二次-49(x-y)二次(2)(x+y)二次/4-(x-y)二次/4
(1)36(x+y)二次-49(x-y)二次
=【6(x+y)】平方-[7(x-y)]平方
=[6(x+y)+7(x-y)][6(x+y)-7(x-y)]
=(6x+6y+7x-7y)(6x+6y-7x+7y)
=(13x-y)(13y-x)
(2)(x+y)二次/4-(x-y)二次/4
=1/4 [(x+y)平方-(x-y)平方]
=1/4(x+y+x-y)(x+y-x+y)
=1/4×2x×2y
=xy