Question

(理)已知两圆⊙C₁:x²+y²+D₁x+E₁y-3=0和⊙C₂:x²+y²+D₂x+E₂y-3=0都经过点A(2,-1),则同时经过点(D₁,E₁)和点(D₂,E₂)的直线方程为

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与⊙C₂都过A(2,-1),

∴

即

∴过(D₁,E₁)和(D₂,E₂)的直线为2x-y+2=0.

答案:A