abc<0 a+b+c<0
①a<0 b<0 c<0
x=|a|/a+|b|/b+c/|c|
=-a/a-b/b-c/c
=-3
∴1/x-92x+2
=-1/3+276+2
=277又2/3
②a,b,c有一个小于0 两个大于0
x=|a|/a+|b|/b+c/|c|
=1
∴1/x-92x+2
=1-92+2
=-89.
abc<0 a+b+c<0
①a<0 b<0 c<0
x=|a|/a+|b|/b+c/|c|
=-a/a-b/b-c/c
=-3
∴1/x-92x+2
=-1/3+276+2
=277又2/3
②a,b,c有一个小于0 两个大于0
x=|a|/a+|b|/b+c/|c|
=1
∴1/x-92x+2
=1-92+2
=-89.