Question

If $2 + i$ is a root of equation $x^{3} - 5 x^{2} + 9x - 5 = 0$, then the other roots are

• A. $1$ and $2-i$
• B. $-1$ and $3+i$
• C. $0$ and $1$
• D. $-1$ and $i-2$

Answer 1

Answer: (A)

Since complex roots always occur in pairs
So, $2 - i$ is also a root of given equation.
Given equation is $x^{3} - 5x^{2} + 9x- 5 = 0$.
$x = 1$ satisfies this equation.
$\therefore $ Other roots are $(2 - i)$ and $1$ .