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复数z满足z(2-i)=1+7i,则复数z的共轭复数为()A.-1-3iB.-1+3iC.1+3iD.1-3i

题目详情

复数z满足z(2-i)=1+7i,则复数z的共轭复数为(  )

A. -1-3i

B. -1+3i

C. 1+3i

D. 1-3i

▼优质解答
答案和解析
∵z(2-i)=1+7i,
z=
1+7i
2-i
=
(1+7i)(2+i)
(2-i)(2+i)
=
-5+15i
5
=-1+3i,
.
z
=-1-3i.
故选:A.