Question

Solve the equation by graphically method: x +y = 3;2x + 5y = 15

Answer 1

Graph of the equation $2x+5y=15$

$\Rightarrow y=\frac{15-2x}{5}$

Let us assign the values of $x$ by constructing a table:

$x$	$-4$	$-3$	$-2$	$-1$	$0$	$1$	$2$	$3$	$4$
$y=\frac{15-2x}{5}$	$4.6‬$	$4.2‬$	$3.8‬$	$3.4$	$3$	$2.6$	$2.2$	$1.8‬$	$1.4$

Plot the points $(-4,4.6),(-3,4.2),(-2,3.8),(-1,3.4),(0,3),(1,2.6),(2,2.2),(3,1.8)$ and $(4,1.4)$ on the graph sheet.

Join the points using a ruler.

Graph of the equation $x+y=3$

$\Rightarrow y=3-x$

Let us assign the values of $x$ by constructing a table:

$x$	$-4$	$-3$	$-2$	$-1$	$0$	$1$	$2$	$3$	$4$	$5$
$y=3-x$	$7$	$6$	$5$	$4$	$3$	$2$	$1$	$0$	$-1$	$-2$

Plot the points $(-4,7),(-3,6),(-2,5),(-1,4),(0,3),(1,2),(2,1),(3,0),(4,-1)$ and $(6,-2)$ on the graph sheet.

Join the points using a ruler.

The point of intersction of both the lines are at $(0,3)$ is the solution of the above equations.

$\therefore x=0,y=3$