For a pair of equations $2x + 3y = 1$ and $3x - 2y = 8$,in usual notations $a_{1}b_{2} - a_{2}b_{1} = \dots$

$8$ men and $12$ women can finish a piece of work in $10$ days. While $6$ men and $8$ women can finish it in $14$ days. Find the time taken by one man alone and that by one woman alone to finish the work.

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

One equation of a pair of dependent linear equations is $-5x + 7y = 2$. The second equation can be

The solution set of the pair of equations $2x + 3y = 4$ and $6x + 9y = 17$ is ............

By the method of substitution,solve the following pair of linear equations: $3x - 7y = 18, 6x - 14y = 12$.