Question

Solve it:
If the sum of zeroes of the quadratic polynomial $3x^2-kx+6$ is $3$ then find the value of $K$

Answer 1

In a general quadratic equation of form $a{x}^2+bx+c=0$, sum of roots are by $\frac{-b}{a}$.

In the given quadratic equation, $3x^2-kx+6=0$

$a=3,b=-k,c=6$

Sum of roots $=\frac{-b}{a}=\frac{-(-k)}{3}=\frac{k}{3}$

and sum of roots is given 3

$\Rightarrow \frac{k}{3}=3$

$\Rightarrow k=9$