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Algebra Difficulty 2.8 Junior Find the answer

If the complex number xx satisfies zi=1+2izi=1+2i, then the conjugate of zz is

Pick one

Solution

Analysis

This question tests the operation of multiplication and division in the algebraic form of complex numbers and examines the concept of conjugate complex numbers. It is a basic question. Transform the given equation, then simplify it using the operation of multiplication and division in the algebraic form of complex numbers, and finally, determine the answer using the concept of conjugate complex numbers.

Solution

Given zi=1+2izi=1+2i, we have z=1+2ii=−i(1+2i)=2−iz= \frac{1+2i}{i}=-i(1+2i)=2-i,
Therefore, z=2−iz=2-i, and thus zˉ=2+i\bar{z}=2+i.
Hence, the correct option is B\boxed{\text{B}}.

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Source: NuminaMath-1.5, licensed Apache-2.0. Statement and solution reproduced as published; topic and difficulty added by this site.