### Topic

#### Homework Help? D:

I can't seem to understand my Algebra I homework. It's graphing equations and I know we've done it before, I'm sure, but I just can't remember the steps. Here's an example:

~~~~~
Plot the following on a graph:
x - 3y = 9
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If there's anyone who could possibly help, that would be amazing. Just list the steps to solving the equation is all I need.

Thank you so much :D

### Replies

• My lazy way of doing it is
1. Pick an x-value, say 0.
2. Substitute it into the equation and solve for y.  Now you have an ordered pair.
3. Plot the ordered pair.
4. Repeat steps 1–3 with another couple x-values.  Now you have several points on your graph.  If you did it right, they're all on a line.  If not, you made a mistake, so check your steps in solving for y.
5. Draw a line through your points.

You could also pick y-values and solve for the corresponding x-values.
• Thank you SOSOSO much <3 You're such a life saver :D
• First, recognise that this is a straight line (linear) graph*. The laziest way to draw this graph is to simply take the x-intercept (where the line cuts the x-axis, so at this point y = 0) and the y-intercept (where the line cuts the y-axis, so x = 0), draw a line between the two and extend the line in both directions.

* If you know about polynomials, you can see that this is a linear graph because the largest x and y terms are to the power of 1. If you haven't learnt about polynomials yet, don't worry about this.