Question

Solution set of $(x+1)(x-1{)}^2(x-2)\ge 0$ is

• A. $(-\infty ,-1]\cup [2,\infty )$
• B. $[-1,2]$
• C. $(-1,2)$
• D. $(-\infty ,-1]\cup \left\{1\right\}\cup [2,\infty )$

Answer 1

The correct option is D $(-\infty ,-1]\cup \left\{1\right\}\cup [2,\infty )$

$(x+1)(x-1{)}^2(x-2)=0$
Critical points are $-1,1,2$


$\therefore x\in (-\infty ,-1]\cup \left\{1\right\}\cup [2,\infty )$