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

Show that the points $A(1, 2)$,$B(-1, -16)$,and $C(0, -7)$ lie on the graph of the linear equation $y = 9x - 7$.

If $(2,3)$ is a solution of the equation $7x - 3y = a$ and $(a, a+1)$ is a solution of the equation $2x + y = b$,find the values of $a$ and $b$.

If $(5, 2)$ is one of the solutions of the equation $x + 3y = k$,then $k = \ldots$

Examine which of the following points are solutions of the equation $3x - 2y = 12$,and which are not:
$(1) (0, -6)$
$(2) (2, 3)$
$(3) (2, -3)$
$(4) (-4, 0)$
$(5) (-2, -9)$
$(6) (6, 4)$

Express the following linear equation in the form $ax + by + c = 0$ and indicate the values of $a$,$b$,and $c$: $x = 3y$.