Question

The roots of the equation $x^3-3x-2=0$ are:

• A. $-1,-1,2$
• B. $-1,1,-2$
• C. $-1,2,-3$
• D. $-1,-1,-2$

Answer 1

The correct option is A

$-1,-1,2$

Explanation for the correct option

Given, $x^3-3x-2=0$

By factorising,

$\begin{array}{cc}& x^3-3x-2=0\\ \Rightarrow & (x+1)(x^2-x-2)=0\\ \Rightarrow & \left(x+1\right)\left[x^2+x-2x-2\right]=0\\ \Rightarrow & \left(x+1\right)\left(x+1\right)\left(x-2\right)=0\\ \Rightarrow & {(x+1)}^2(x-2)=0\end{array}$

$x=-1,-1,2$

Hence the correct option is option A.