Question

What is the slope and y-intercept of the line `9x+3y=12`?

Answer 1

The slope is `-3` and the y-intercept is `4`.

Explanation:

It helps if you put your equation into the standard linear form of `y=mx+b`. In this form, `m` is always the slope, and `b` is always the y-intercept.

To get it into standard form, you need to isolate `y`. To do this, I can first move the `9x` by subtracting it from each side of the equation, giving me:

`3y = -9x + 12`

Then, I would divide each side by 3, to isolate the `y`. The distributive property requires that both `-9y` and `12` be divided by 3 as well. This gives me:

`y = -3x +4`

Now I have my equation in standard form, and can see that the slope is `-3` and the y-intercept is `4`. That can be reflected by graphing the line as well: graph{-3x +4 [-4.834, 5.166, -0.54, 4.46]}