Question

If one root of the quadratic equation $3y^2-ky+8=0$ is $\frac{2}{3}$, then find the value of $k$.

• A. 14
• B. 13
• C. 12
• D. 11

Answer 1

Answer: (A)

14

$\frac{2}{3}$ is a root of the equation, $3y^2-ky+8=0$, then it should satisfy the given equation.
Put $y=\frac{2}{3}$

$\therefore 3(\frac{2}{3}{)}^2-k\left(\frac{2}{3}\right)+8=0$

$\therefore \frac{4}{3}-\frac{2k}{3}+8=0$

$\therefore 4-2k+24=0$
$\therefore k=14$