拜托了①(a-b)^4-(a+b)^2 ②2(x-y)(x+y)-(x+y)^2-(x-y)^2

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拜托了①(a-b)^4-(a+b)^2 ②2(x-y)(x+y)-(x+y)^2-(x-y)^2
拜托了①(a-b)^4-(a+b)^2 ②2(x-y)(x+y)-(x+y)^2-(x-y)^2

拜托了①(a-b)^4-(a+b)^2 ②2(x-y)(x+y)-(x+y)^2-(x-y)^2
①(a-b)^4-(a+b)^2=[(a-b)²+a-b]*[(a-b)²-a-b]
②2(x-y)(x+y)-(x+y)^2-(x-y)^2 =-[(x+y)²-2(X+y)(x-y)+(x-y)²]=-[(x+y)-(x-y)]²=-4y²

1:(a-b)^4-[(a-b)^2+4ab]=(a-b)^4-(a-b)^2-4ab.2:4y^2