Question

If p,q & r are the roots of a cubic polynomial $a{x}^3+b{x}^2+cx+d$, then what will be p+q+r?

• A. $-\frac{b}{a}$
• B. $-\frac{c}{a}$
• C. $\frac{b}{a}$
• D. $\frac{c}{a}$

Answer 1

The correct option is A $-\frac{b}{a}$

We know that for cubic equation $a{x}^3+b{x}^2+cx+d$
Sum of roots = $-\frac{b}{a}$
Therefore, $p+q+r=-\frac{b}{a}$