Question

已知:1/a+1/b+1/c=0,求证:a^2+b^2+c^2=(a+b+c)^2

拜托了，各位，急需

Answer 1

右式-左式=2ab+2bc+2ca
1/a+1/b+1/c=0，所以左右×abc得bc+ac+ab=0
所以2ab+2bc+2ca=0
所以右式=左式

Answer 2

a^2+b^2+c^2-(a+b+c)^2
=-2ab-2bc-2ac
=-2abc(1/a+1/b+1/c)
=0