How do you graph #-3x+7y=21#?
Make it into a y= equation first.
From this equation, we can see that this line would have a y intersection at 3. So label the point at (0,3)
We also know that the coefficient before the x represents the slope. So slope is 3/7. Slope is also
Since we found point (0,3) you can add 3 on the y coordinate, and 7 on the x coordinate to find other points. Then taking those points, you can draw the line to your graph.
Your graph should look something like this