Quadratic formula is also called as formula. (Aryabhatta, Bhaskara, Sreedharacharya)

Which of the following is a quadratic equation?

Which of the following is not a quadratic equation?

If $x=3$ is a solution of the equation $3x^2+\left(k-1\right)x+9=0$, then $k$ is equal to

The sum of the roots of the equation $x^2-6x+5=0$ is

The value of $\sqrt{6+\sqrt{6+\sqrt{6+.......\infty }}}$ is

If $a{x}^2+bx+c=0$ has equal roots, then $c$ equals

If $4x^2-12x+9=0$ has equal roots, then the roots are: