Question 24253
You start by making a table and choosing values for x and then solving the equation for y.
y-x=-5
when x=0;
y-(0)=-5
y=-5
then y=-5
when x=1
y-(1)=-5
y=-5+1
y=-4
then y=-4
when x=2
y-(2)=-5
y=-5+2
y=-3
then y=-3 
Now you have three points, so you plot them on the graph and draw a line connecting them.
{{{graph (400,400, -6,6,-6,6, y=x-5)}}}