(3a-6b)/(a+b) - (5a-6b)/(a-b) - (4a-5b)/(a+b) - (7a-8b)/(a-b) 快

(3a-6b)/(a+b) - (5a-6b)/(a-b) - (4a-5b)/(a+b) - (7a-8b)/(a-b) 快
(3a-6b)/(a+b) - (5a-6b)/(a-b) - (4a-5b)/(a+b) - (7a-8b)/(a-b)
快

(3a-6b)/(a+b) - (5a-6b)/(a-b) - (4a-5b)/(a+b) - (7a-8b)/(a-b) 快
(3a-6b)/(a+b) - (5a-6b)/(a-b) - (4a-5b)/(a+b) - (7a-8b)/(a-b)
=(3a-6b)/(a+b) - (4a-5b)/(a+b)- (5a-6b)/(a-b) - (7a-8b)/(a-b)
=(3a-6b-4a+5b)/(a+b) - (5a-6b+7a-8b)/(a-b)
=-(a+b)/(a+b) - (12a-14b)/(a-b)
=-1 - (12a-14b)/(a-b)
= - (13a - 15b)/(a-b)
这个问题好像不能化简到 很简单的结果,
如果原来的式子中 的最后一项是 (7a-6b)/(a-b) 的话,就比较好化简了.（这时结果 -13）

(3a-6b)/(a+b) - (5a-6b)/(a-b) - (4a-5b)/(a+b) - (7a-8b)/(a-b)
=(3a-6b)/(a+b) - (4a-5b)/(a+b) - (7a-8b)/(a-b) - (5a-6b)/(a-b)
=（7a-11b)/(a+b)-(12a-14b)/(a-b)
通分
原式=[(7a-11b)(a-b)-(12a-1...

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(3a-6b)/(a+b) - (5a-6b)/(a-b) - (4a-5b)/(a+b) - (7a-8b)/(a-b)
=(3a-6b)/(a+b) - (4a-5b)/(a+b) - (7a-8b)/(a-b) - (5a-6b)/(a-b)
=（7a-11b)/(a+b)-(12a-14b)/(a-b)
通分
原式=[(7a-11b)(a-b)-(12a-14b)(a+b)]/(a^2-b^2)
=(-5a^2+25b^2-16ab)/(a^2-b^2)
只能到这里
希望对你有帮助
祝你学业进步！(*^__^*)

收起

(3a-6b)/(a+b) - (5a-6b)/(a-b) - (4a-5b)/(a+b) - (7a-8b)/(a-b)
=(3a-6b)/(a+b) - (4a-5b)/(a+b) - (5a-6b)/(a-b)-(7a-8b)/(a-b)
=(3a-6b-4a+5b)/(a+b) - (5a-6b+7a-8b)/(a-b)
=(-a-b)/(a+b) - (12a-14b)/(a-b)
=-1- (12a-14b)/(a-b)
=-(a-b)/(a-b)-(12a-14b)/(a-b)
=-(a-b+12a-14b)/(a-b)
=-(13a-15b)/(a-b)

(3a-6b)/(a+b) - (5a-6b)/(a-b) - (4a-5b)/(a+b) - (7a-8b)/(a-b) =[(3a-6b)/(a+b)- (4a-5b)/(a+b)]-[(5a-6b)/(a-b) +(7a-8b)/(a-b)]= -(a+b)/(a+b)-(12a-14b)/(a-b)=-1-(12a-14b)/(a-b)=-(13a-15b)/(a-b)

原式=(3a-6b)/(a+b) - (4a-5b)/(a+b)- [(5a-6b)/(a-b)+(7a-8b)/(a-b) ]
=(3a-6b-4a+5b)/(a+b)-(5a-6b+7a-8b)/(a-b)
=(-a-b)/(a+b)-(12a-14b)/(a-b)
=-(a+b)/(a+b)-2(6a-7b)/(a-b)
=2(7b-6a)/(a-b)-1
祝你开心

1

(3a-6b)/(a+b) - (4a-5b)/(a+b)- ((5a-6b)/(a-b)+(7a-8b)/(a-b) )
=(3a-6b-4a+5b)/(a+b)-(5a-6b+7a-8b)/(a-b)
=(-a-b)/(a+b)-(12a-14b)/(a-b)
=-(a+b)/(a+b)-2(6a-7b)/(a-b)
=2(7b-6a)/(a-b)-1