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

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

If the graph of the equation $ax + 3y = 21$ passes through the point $(5, 2)$,then the value of $a = \ldots$

If $(3, 2)$ is one of the solutions of $5x - ay = 7$,then $a = \dots$

State whether the following statement is True or False. Justify your answer:
The coordinates of points in the table:

$x$	$0$	$1$	$2$	$3$	$4$
$y$	$2$	$3$	$4$	$-5$	$6$

represent some of the solutions of the equation $x-y+2=0$.

The graph of $y=6$ is a line