Complex Numbers And Quadratic Equations question 817
Question: The roots of the equation $ x^{4}-2x^{3}+x=380 $ are [UPSEAT 2004]
Options:
A) $ 5,-4,\frac{1\pm 5\sqrt{-3}}{2} $
B) $ -5,4,-\frac{1\pm 5\sqrt{-}3}{2} $
C) $ 5,4,\frac{-1\pm 5\sqrt{-}3}{2} $
D) $ -5,-4,\frac{1\pm 5\sqrt{-}3}{2} $
Show Answer
Answer:
Correct Answer: A
Solution:
Given equation is $ x^{4}-2x^{3}+x-380=0 $ Using remainder theorem we get $ (x-5)(x+4)(x^{2}-x+19)=0 $ $ x-5=0 $ , $ x-4=0 $ and $ x^{2}-x+19=0 $ $ x=5 $ , $ x=-4 $ and $ x=\frac{-1\pm 5\sqrt{-3}}{2} $ .
BETA
