The value of the discriminant of the quadratic equation $5x^{2} + x + 2 = 0$ is ..... .

Solve the following equation using the method of 'completing the square': $x^{2}+3x-5=0$.

Examine whether the following equation is quadratic or not: $(x+6)(x+5)=0$.

Obtain the roots of the following quadratic equation by using the quadratic formula: $2x^{2} + 5\sqrt{3}x + 6 = 0$.

At $t$ minutes past $2\, pm$, the time needed by the minute hand of a clock to show $3\, pm$ was found to be $3\, minutes$ less than $\frac{t^{2}}{4}$ $minutes$. Find $t$.

Solve the following equation using the quadratic formula,if the equation has a solution in $R$: $\sqrt{2} x^{2} + 7x + 5\sqrt{2} = 0$