Question

(理)已知兩圓⊙C₁:x²+y²+D₁x+E₁y-3=0和⊙C₂:x²+y²+D₂x+E₂y-3=0都經過點A(2,-1),則同時經過點(D₁,E₁)和點(D₂,E₂)的直線方程為

A.2x-y+2=0        B.x-2y-2=0        C.x-2y+2=0          D.x+y-2=0

Answer 1

(理)解析:∵⊙C₁與⊙C₂都過A(2,-1),

∴

即

∴過(D₁,E₁)和(D₂,E₂)的直線為2x-y+2=0.

答案:A