2、已知a+b=-c且abc不等于0,求a(1/b+1/c)+b(1/a+1/c)+c(1/a+1/求大神帮助

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2、已知a+b=-c且abc不等于0,求a(1/b+1/c)+b(1/a+1/c)+c(1/a+1/求大神帮助
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2、已知a+b=-c且abc不等于0,求a(1/b+1/c)+b(1/a+1/c)+c(1/a+1/求大神帮助
2、已知a+b=-c且abc不等于0,求a(1/b+1/c)+b(1/a+1/c)+c(1/a+1/求大神帮助

2、已知a+b=-c且abc不等于0,求a(1/b+1/c)+b(1/a+1/c)+c(1/a+1/求大神帮助
a(1/b+1/c)+b(1/a+1/c)+c(1/a+1/b) =a(b+c)/(bc)+b(a+c)/(ac)+c(a+b)/(ab) =-a^2/(bc)-b^2/(ac)-c^2/(ab) =-(a^3+b^3+c^3)/(abc) =-[(a+b)(a^2-ab+b^2)+c^3]/(abc) =-c(c^2-a^2+ab-b^2)/(abc) =-[(c+a)(c-a)+ab-b^2]/(ab) =b(c-a-a+b)/(ab) =(b+c-2a)/a =(-a-2a)/a =3a/a =3