Do the equations $4x + 3y - 1 = 5$ and $12x + 9y = 15$ represent a pair of coincident lines? Justify your answer.

For a pair of equations $13x - 7y = 19$ and $7x - 13y = 31$,find the value of $x + y$.

Ankita travels $14 \,km$ to her home partly by rickshaw and partly by bus. She takes half an $hour$ if she travels $2 \,km$ by rickshaw and the remaining distance by bus. On the other hand,if she travels $4 \,km$ by rickshaw and the remaining distance by bus,she takes $9 \,minutes$ longer. Find the speed of the rickshaw and of the bus (in $km/h$).

The graph of the equation $\ldots \ldots \ldots \ldots$ is parallel to the $X$-axis.

If $\frac{x}{2} = \frac{6}{y} = 3$,then $x + y = \ldots$

The digit at the ten's place is $4$ in a two-digit number,and the product of both the digits is four times greater than the digit at the ten's place. Find the number.