# How do you solve  x+y=8, y-x=8 by graphing?

May 4, 2018

Answer is #(0,8), intersection of graphs

#### Explanation:

First, we make $y$ the subject of the equation:

$x + y = 8$
$y = - x + 8$-----> by subtracting $x$ both sides

$y - x = 8$
$y = x + 8$----> by adding $x$ both sides

Now we have:
$y = - x + 8$ (red line graph)
$y = x + 8$ (blue line graph)

Create a graph to locate the intersection of the equations. The intersection of the system of equations is the solution.
by plotting the graph, see the attached, we get intersection at $\left(0 , 8\right)$, hence the solution is $\left(0 , 8\right)$