Question

Find $x+y$ for the following system of linear equations graphically,
$x-y=1$ and $2x+y=8$.

Answer 1

Given linear equation are $x-y=1$ and $2x+y=8$

let us find two points on the line $x-y=1$

$x-y=1\Rightarrow x-1=y$

For $x=1\Rightarrow y=0$

For $x=2\Rightarrow y=1$

Now we find two points on the line $2x+y=8$

$2x+y=8\Rightarrow y=8-2x$

For $x=1\Rightarrow y=6$

For $x=2\Rightarrow y=4$

Lets us plot those line on graph

So we see lines intersect at point $(3,2)$. Hence $x=3,y=2$

Hence $(x+y)=(3+2)$

$=5$