How do I sketch my graph of X+Y=3?

Please help! I don't understand. Do I need to solve this like the rest of my previous graphs if so, then how? Please Help!

The equation represents a line.

Two points determine a line.
The easiest two points to find on the line are the axis intercepts.

When x=0, y=3
When y=0, x=3

So, plot the points (0,3) and (3,0) and draw a line through them.