Question

Let $f(x)$ be a cubic polynomial which has local maximum at $x=-1$ and $f^{\prime }(x)$ has a local minimum at $x=1$. If $f(-1)=10$ and $f(0)=5$.
If $x_1,x_2,x_3$ are the real roots of $f(x)=0$ then ${\left[x_1\right]}^2+{\left[x_2\right]}^2+{\left[x_3\right]}^2$ is equal to
[Note : [ $k]$ denotes the greatest integer less than or equal to $k$. ]

• A. 20
• B. 21
• C. 22
• D. 25

Answer 1

Answer: (D)

Correct answer is (d) 25