Solve the following pair of linear equations by the method of substitution: $x + y = 7$ and $5x + 12y = 7$.

Use the method of elimination to find the solution of the following pair of linear equations: $2x + y = 4$ and $x + 3y = 7$.

The standard form of the equation $3x = 2y - 1$ is..........

The sum of a two-digit number and the number obtained by interchanging its digits is $110$. If the number obtained by subtracting $10$ from the original number exceeds five times the sum of the digits of the original number by $4$,then find the original number.

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

The solution set of the pair of equations $x = -2$ and $y = 3$ is: