well first you have to get x and y on separate sides so subtract x by both sides to put x on the right side.
now you have y = 5 - x
to graph that let's throw in some numbers for x and y and make a function table
x, y
1, 4
2, 3
3, 2
4, 1
5, 0
6, -1
and so forth
as you can see as x increases in value, y decreases in value
all you have to do now is plot those points on a graph