If the sum of two numbers is $20$ and their difference is $8,$ then the larger number is ...........

Solve the following pairs of equations:
$\frac{1}{2x} - \frac{1}{y} = -1$
$\frac{1}{x} + \frac{1}{2y} = 8, \quad x, y \neq 0$

For eliminating $y$ from the equations $3x - 2y = 1$ and $5x + y = 6$,the second equation should be multiplied by

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

The sum of the digits of a two-digit number is $9$ and the difference is $1$. The number is ............

Graphically,solve the following pair of equations:
$2x + y = 6$
$2x - y + 2 = 0$
Find the ratio of the areas of the two triangles formed by the lines representing these equations with the $x$-axis and the lines with the $y$-axis.