如题所述
a2(a一b)2一b2(a一b)2=(a一b)2(a2一b2)=(a一b)2(a+b)(a一b)=(a一b)3(a+b),,,(a2+4)2一16a2二(a2+4一4a)(a2+4+4a)=(a一2)2(a+2)2
2x2+2x+1/2二2(x2+x+1/4)二2(x+1/2)2