........ also mentioned a method to find the solution of quadratic equation.

In quadratic equation $ax^{2} + bx + c = 0$,where $a \neq 0$,$b = 0$,and $D > 0$,then both the roots of the equation are .....

If $-3$ is a solution of $2x^{2} + 5x + k = 0$,then $k = \ldots$

$A$ train,travelling at a uniform speed for $360\, km$,would have taken $48\, min$ less to travel the same distance,if its speed were $5\, km/h$ more. Find the original speed of the train (in $km/h$).

For a quadratic equation $ax^2 + bx + c = 0$,if $\ldots \ldots \ldots \ldots$ then the roots are distinct and rational.

The faster train takes $1$ hour less than the slower train for covering a $400\, km$ distance. If the speed of the slower train is $20\, km/hr$ less than the speed of the faster train,find the speed of the slower train.