1) If the conjugate of $(x+iy)(1-2i) $ is (1+i) , then A) $x+iy=1-i$ B) $x+iy=\frac{1-i}{1-2i}$ C) $x-iy=\frac{1-i}{1+2i}$ D) $x-iy=\frac{1-i}{1+i}$ Answer: Option BExplanation:We have , Conjugate of (x+iy)(1-2i) is 1+i i.e, (x-iy)(1+2i)=1+i $\Rightarrow$ $x-iy= \frac{1+i}{1+2i}$ Taking conjugate both sides , we get $x+iy=\frac{1-i}{1-2i}$
