帮帮我忙： 9.化简1/(a+b)+1/(a-b)-(a-b)/(a^2+ab+b^2)-(a+b)/(a^2-ab+b

来源：学生作业帮编辑：作业帮分类：数学作业时间：2024/05/14 07:29:34

帮帮我忙： 9.化简1/(a+b)+1/(a-b)-(a-b)/(a^2+ab+b^2)-(a+b)/(a^2-ab+b^2)
14.已知a,b,c互不相等,求(2a-b-c)/[(a-b)(a-c)]+(2b-c-a)/[(b-c)(b-a)]+(2c-a-b)/[(c-a)(c-b)]

9.化简1/(a+b)+1/(a-b)-(a-b)/(a^2+ab+b^2)-(a+b)/(a^2-ab+b^2)
=[1/(a+b)-(a+b)/(a^2-ab+b^2)]+[1/(a-b)-(a-b)/(a^2+ab+b^2)]
=[(a^2-ab+b^2)-(a+b)^2]/(a^3+b^3)+[(a^2+ab+b^2)-(a-b)^2]/(a^3-b^3)
=-3ab/(a^3+b^3)+3ab/(a^3-b^3)
=3ab[1/(a^3-b^3)-1/(a^3+b^3)]
=3ab[(a^3+b^3)-(a^3-b^3)]/(a^6-b^6)
=6ab^4/(a^6-b^6)
14.已知a,b,c互不相等,求(2a-b-c)/[(a-b)(a-c)]+(2b-c-a)/[(b-c)(b-a)]+(2c-a-b)/[(c-a)(c-b)]
=(2a-b-c)/[(a-b)(a-c)]-(2b-c-a)/[(b-c)(a-b)]+(2c-a-b)/[(a-c)(b-c)]
=[(2a-b-c)(b-c)-(2b-c-a)(a-c)+(2c-a-b)(a-b)]/[(a-b)(a-c)(b-c)]
=0/[(a-b)(a-c)(b-c)]
=0

帮帮我忙： 9.化简1/(a+b)+1/(a-b)-(a-b)/(a^2+ab+b^2)-(a+b)/(a^2-ab+b （a-b)(a^2+ab+b) 化简计算ab/(a+b-1)(a+b)+ab/(a+b)(a+b+1)+ab/(a+b+1)(a+b+2)+.+ab/(a+ a+b/2ab 2AB/A+B a(a-1)-(a×a-b)=-5,求(a×a+b×b)÷2-ab 化简 (a²+b²/a²-b²-a-b/a+b)÷2ab/(a-b)(a+b)& 若a/b=2 则a*a-ab+b*b/a*a+b*b等于? 急……ab/(a+b-1)(a+b) + ab/(a+b)(a+b+1) + ab(a+b+1)(a+b+2) + …… 计算：a/b(a-b)-b/a(a-b)；（1/a+1/b）÷a²+2ab+b²/a+b. ab+a+b+1 化简 b²-a²/a²-ab÷（a+(2ab+b²/a))·(1/a+1/b)