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Answer

The correct answer is A. The y-intercept of the line is (0, 2). The slope is three, which means it has a rise
of three and a run of one.

Writing Linear Equations from Graphs

Now that you can graph lines from equations, let's work on going the other direction: writing an equation of
a line from its graph. As you can probably imagine, this can be done in several different ways; here are
two basic methods.

Depending on what the line looks like on the graph, you may be able to easily determine the y-intercept
and count out the slope to another obvious point. Then all you have to do is put it into the y = mx + b form.

Unfortunately, lines do not always cross the y-axis at a gridline, so it is often better to choose two other
obvious points and calculate the slope and the y-intercept. It takes a bit longer, but it is much more
accurate. (By the way, this also allows you to write the equation of line from any two points, even without
seeing the graph.)