Find the common solution of the equations $x + y = 0$ and $x - y = 0$.

Any point on the $y$-axis is of the form

Give equations of four lines passing through the point $(3, 5)$.

$A$ linear equation in two variables is of the form $ax + by + c = 0$,where

Express the following linear equation in the form $ax + by + c = 0$ and indicate the values of $a, b,$ and $c$ in each case:
$\pi x - 3y = 18$

State whether the following statement is True or False and justify your answer:
Every point on the graph of a linear equation in two variables does not represent a solution of the linear equation.