For the pair of equations $2x + 3y = 10$ and $3x - y = 4$,find the value of $x$.

If the following pair of equations is consistent (unique solution),then find the value of $k$:
$x - ky = 2$
$3x + 2y = -5$

Solve the following pair of equations: $2x + y = \frac{7xy}{3}, x + 3y = \frac{11xy}{3}$

Solve the following pair of linear equations using a graph: $x+y=7$,$5x+2y=20$.

If $7x - 9y = 25$ and $9x - 7y = 23$,then $x + y = \dots$

$A$ motor boat can travel $30 \, km$ upstream and $28 \, km$ downstream in $7 \, hours$. It can travel $21 \, km$ upstream and return in $5 \, hours$. Find the speed of the boat in still water and the speed of the stream (in $km/h$).