If the point $(-2, 5)$ lies on the graph of the equation $ax + 3y = 7$,find the value of $a$.

Write $5 x-3 y=15$ in the standard form of a linear equation in two variables.

Express the following linear equation in the form $ax + by + c = 0$ and indicate the values of $a, b$ and $c$ in each case:
$3x = 2y + 1.\overline{5}$

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

The work done by a body on application of a constant force is the product of the constant force and the distance travelled by the body in the direction of force. Express this in the form of a linear equation in two variables and draw its graph by taking the constant force as $3$ units. What is the work done when the distance travelled is $2$ units? Verify it by plotting the graph.

If the point $(a, a-2)$ lies on the graph of the equation $3x + 5y = 30$,find the value of $a$.