A.x2+y2-10x+9=0 B.x2+y2-10x+16=0 C.x2+y2+10x+16=0 D.x2+y2+10x+9=0
A.3,24,33 B.31,47,147 C.133,153,193 D.102,132,159
A.-5 B.5 C.-10 D.10
A.α⊥γ且l⊥m B.α⊥γ且m//β C.m//β且l⊥m D.α//β且α⊥γ
A.a2-2a-2b-3=02 B.a2+2a+2b+5=0 C.a2+2b2+2a+2b+1=0 D.3a2+2b2+2a+2b+1=02
A.1个平面 B.4个平面 C.1个或4个平面 D.无法确定
a≥2。