समीकरण के रूप में $2 x+9=0$ का ज्यामितीय निरूपण कीजिए।

$(i)$ एक चर वाले

$(ii)$ दो चर वाले

$(i)$ $2 x +9=0[$ An equation in one variable $]$

We have : $2 x+9=0 \Rightarrow 2 x=-9 \Rightarrow x=\frac{-9}{2}$

which is a linear equation in one variable ${ }^{\prime} x ^{\prime}$ only. Its solution is the point $\frac{-9}{2}$ on the number line as shown below.

$(ii)$ $2 x +9=0$ [An equation in two variables]

We can write $2 x+9=0$ as $2 x+0 y+9=0$ or $2 x=-9+0 y$

or $x=\frac{-9+0 y}{2}$

$\therefore$ When $y =1, \quad x =\frac{-9+0(1)}{2}=\frac{-9}{2}$

When $y=2, \quad x=\frac{-9+0(2)}{2}=\frac{-9}{2}$

When $y=3$ $x=\frac{-9+0(3)}{2}=\frac{-9}{2}$

Thus, we get the following table :

$x$	$\frac{-9}{2}$	$\frac{-9}{2}$	$\frac{-9}{2}$
$y$	$1$	$2$	$3$

Now, plotting the ordered pairs $\left(\frac{-9}{2},\,1\right),\,\,\left(\frac{-9}{2},\, 2\right),$ and $\left(\frac{-9}{2}, \,3\right)$ on a graph paper and joining them, we get a line $PQ$ as solution of $2 x +9=0$.