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哥们,第一个括号前少了个a吧?
a(1/b+1/c) + b(1/c+1/a )+ c(1/a+1/b)
=a/b + a/c + b/c + b/a + c/a + c/b
=(a/b + c/b + b/b -1) + (a/c + b/c + c/c -1) + (b/a + c/a a/a -1)
=-3
a(1/b+1/c) + b(1/c+1/a )+ c(1/a+1/b)
=a/b + a/c + b/c + b/a + c/a + c/b
=(a/b + c/b + b/b -1) + (a/c + b/c + c/c -1) + (b/a + c/a a/a -1)
=-3
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