Math Chapter Wise Complex Number, De Moivre's Theorem And Nth Root Of Unity English MCQ JDD-75-PGT TIER II-X-15 28.06.2015 Q.If 5 (x iy) a ib + = + + = + + = + + = + then 5 (y ix) + + equals– Aa + bi Ba – bi Cb + ai Db – ai Show answer Correct answer: b + ai