So the easiest way to do this is to convert this standard form equation into slope-intercept form, which is y = mx+b (m = slope, b = y-intercept). The slope indicates whether the line is going upwards and downwards and at what rate, and the y-intercept is where the line crosses the y-axis.
Firstly, subtract both sides by 6x:
Next, divide both sides by 8 and your slope-intercept form will be:
So with this equation, since the slope is negative, the line is going downwards. You will graph this line so that when x increases by 3, y decreases by 2 and so that the line passes (0,-4). Here are some of the points on this line to help you:
(0,-4), (3, -6), (6,-8), etc.