tzofebu8
幼苗
共回答了18个问题采纳率:77.8% 举报
1、(a^2+a+1)(a^2-6a+1)+12a^2
=[(a^2+1)+a][(a^2+1)-6a]+12a^2
=(a^2+1)^2-5a*(a^2+1)+6a^2
=(a^2-3a+1)(a^2-2a+1)
=[a-(3+根号5)/2][a-(3-根号5)/2](a-1)^2;
2、(x+y)^4+(x^2-y^2)^2+(x-y)^4
=[(x+y)^4+2(x^2-y^2)^2+(x-y)^4]-(x^2-y^2)^2
=[(x+y)^2+(x-y)^2]^2-(x^2-y^2)^2
=[(x+y)^2+(x-y)^2+(x^2-y^2)][(x+y)^2+(x-y)^2-(x^2-y^2)]
=(3x^2+y^2)(x^2+3y^2)
1年前
2