If the roots of the equation $6x^2-7x+K=0$ are rational, then is equal to–

Question

If the roots of the equation $6x^2-7x+K=0$ are rational, then is equal to:
$1)$ $-2$
$2)$ $-1,-2$
$3)$ $-2$
$4)$ $1,2$

Answer 1

$\sqrt{7^2-4\times6\times K}$ is rational when $K=1$ or $2$.