A.λ=μ＞0                     B.λ=μ＜0

C.λ、μ∈(-∞,0)                D.λ、μ∈（0，+∞）

A.b-a＞0                       B.a³+b³＜0

C.a²-b²＜0                      D.b+a＞0

设a,b,c不全为0，且a+b+c=0，则

1. A.
   ab+bc+ca>0
2. B.
   ab+bc+ca<0
3. C.
   ab,bc,ca均为负数
4. D.
   abc<0

A.ab＜0                         B.ab＞0

C.ab≥0                         D.ab=0

A.ab＞ac                                     B.c(b-a)＞0

C.cb²＜ab²                                  D.ac(a-c)＜0

A.12x+35y-185=0                         B.5x-8y-25=0

C.12x+35y+185=0或x=5                   D.12x+35y±185=0