3x - y = 6
Let's graph this by finding and plotting the x- and y-intercepts:
x-int.: Let y = 0 and solve for x: 3x = 6, and x = 2. x-int. is (2,0). Plot this.
y-int.: Let x = 0 and solve for y: -y = 6 and y = -6. y-int. is (0, -6). Plot this.
Now draw a str. line thru both points.