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根号11肯定大于3,小于4
所以,a=3,b=根号11 - 3
a^2-b^2 = (3+根号11 -3)(3-根号11 + 3)=根号11 * (6-根号11) = 6根号11 -11
答案 6根号11 -11
(a-b)^2 = a^2+b^2-2ab = 16+5+8根号5 = 21+8根号5
(b-c)^2 = b^2+c^2-2bc = 21-8根号5
(a-b)(b-c)=ab-ac-b^2+bc=16-5=11
a^2+c^2+b^2-ab-bc-ac
=a^2+b^2-2ab+b^2+c^2-2bc+ab-ac-b^2+bc
=21+8根号5+21-8根号5+11
=53
应该都对哦
1年前
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