The solution set of a pair of equations $x=6$ and $y=4$ is .........

By the graphical method,find whether the following pair of equations are consistent or not. If consistent,solve them.
$x - 2y = 6$
$3x - 6y = 0$

The graph of the pair of equations $x+y=7$ and $3x+3y=21$ is:

For what value$(s)$ of $k$ does the pair of equations $kx + 3y = k - 3$ and $12x + ky = k$ have no solution?

$A$ fraction becomes $\frac{1}{4}$ if $2$ is subtracted from the numerator and $3$ is added to the denominator. If $6$ is added to the numerator and the denominator is multiplied by $3$,it becomes $\frac{2}{3}$. Find the fraction.

Solve the following pair of linear equations by the method of substitution: $3x + y + 1 = 0$ and $2x - 3y + 8 = 0$.