Solve the following system of equations graphically.
$2 x-3 y+6=0$
$2 x+3 y-18=0$
Also, find the area of the region bounded by these two lines and y-axis.
The given equations are:
$2 x-3 y+6=0$$\ldots \ldots . .(i)$
$2 x+3 y-18=0$$\ldots \ldots . .(i i)$
Putting $x=0$ in equation (i) we get:
$\Rightarrow 2 \times 0-3 y=-6$
$\Rightarrow y=2$
$x=0, y=2$
Putting $y=0$ in equation (i) we get:
$\Rightarrow 2 x-3 \times 0=-6$
$\Rightarrow x=-3$
$x=-3, \quad y=0$
Use the following table to draw the graph
Draw the graph by plotting the two points $A(0,2), B(-3,0)$ from table.
$2 x+3 y-18=0$.(ii)
Putting $x=0$ in equation $(i i)$ we get:
$\Rightarrow 2 \times 0+3 y=18$
$\Rightarrow y=6$
$x=0, \quad y=6$
Putting $y=0$ in equation $(i i)$, we get:
$\Rightarrow 2 x+3 \times 0=18$
$\Rightarrow x=9$
$x=9, \quad y=0$
Use the following table to draw the graph.
Draw the graph by plotting the two points $C(0,6), D(9,0)$ from table.
The two lines intersect at $P(3,4)$.
Hence $x=3, y=4$ is the solution of the given equations.
The area enclosed by the lines represented by the given equations and the $y$-axis
Now,
$\Rightarrow$ Required area $=$ Area of PCA
$\Rightarrow$ Required area $=1 / 2($ base $\times$ height $)$
$\Rightarrow$ Required area $=1 / 2(C A \times P M)$
$\Rightarrow$ Required area $=1 / 2(4 \times 3)$ sq.units
Hence the required area is $6 \mathrm{sq}$. units