Question

if sum of zeroes of the polynomial 3x^- kx+6 is 3 find the value of k?​

Answer 1

Step-by-step explanation:

Given:-

Sum of zeros of polynomial $\sf 3x^2-kx+6$ is 3

To find :-

value of k

Solution:-

Let the zeros are$\sf \alpha\:and\:\beta$

• Here
• a=3
• b=-k
• c=6

As we know that

$\boxed{\sf Sum\;of\:zeros=\dfrac {-b}{a}}$

• Substitute the values

$\\\qquad\quad\displaystyle\sf {:}\longrightarrow \alpha+\beta=3$

$\\\qquad\quad\displaystyle\sf {:}\longrightarrow \dfrac {-b}{a}=3$

$\\\qquad\quad\displaystyle\sf {:}\longrightarrow \dfrac {-(-k)}{3}=3$

$\\\qquad\quad\displaystyle\sf {:}\longrightarrow \dfrac{k}{3}=3$

$\\\qquad\quad\displaystyle\sf {:}\longrightarrow k=3\times 3$

$\\\qquad\quad\displaystyle\sf {:}\longrightarrow k=9$

$\\\\\therefore\sf k=9.$