Question 634883: Are the conditions- a+b+c>0 & abc>0, sufficient to say that a>0,b>0,c>0
is ab+bc+ca>0 required in addition to conclude that a>0,b>0,c>0.
please explain in detail.
Answer by ankor@dixie-net.com(22740)   (Show Source):
You can put this solution on YOUR website! Are the conditions- a+b+c>0 & abc>0, sufficient to say that a>0,b>0,c>0
No, two could be neg and their sum less than the positive number
For example: a=8, b=-2, c=-3, 8-5 > 0 and 8*-2*-3 = 40 >0
:
ab+bc+ca>0 required in addition to conclude that a>0,b>0,c>0.
No. Actually if all the numbers are neg, it would be >0
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