Write the linear equation such that each point on its graph has an ordinate $3$ times its abscissa.

The equation of the $x$-axis is of the form:

Express the following linear equation in the form $ax + by + c = 0$ and indicate the values of $a, b$ and $c$ in each case:
$x = \frac{2}{5}y + 10$

Write the following equation in the standard form $ax + by + c = 0$ and indicate the values of $a, b,$ and $c$ in each case: $2x = 3y$.

Draw the graph of the linear equation in two variables: $y=3x$

Write the following as an equation in two variables:
$2x = 9$