Graphing Lines using Intercepts - Concept 14,475 views

Teacher/Instructor Alissa Fong
Alissa Fong

MA, Stanford University
Teaching in the San Francisco Bay Area

Alissa is currently a teacher in the San Francisco Bay Area and Brightstorm users love her clear, concise explanations of tough concepts

We use many different techniques to graph lines, but one of the most efficient and straightforward, when given the equation of the line, is graphing lines using intercepts. If we are not given a table of values, the easiest two points to find are usually the x- and y-intercepts. Graphing lines using intercepts is not the only method, we can also graph using the slope and the y-intercept.

Whenever you're asked to graph a line,
you have a choice of what method
you want to use.

Some people like to graph lines
by making an X-Y table.
That's where you choose X values, substitute
them in one by one and find the
corresponding Y values.
Use those as points and connect them.

Another method you guys might like to
use is the slope intercept method.
That's where you put your equation
into Y equals MX plus B form.
Your first doc was at B that's
at the Y intercept.
From there you count your slope and make
another point and you connect them.
Be sure to use a ruler.

The method I really want you guys to practice
a little bit more and what you're
going to see in your homework is this
method 3. Finding and connecting
the X and Y intercepts.

The way to find X intercept is to substitute
Y equals 0. The way to find
the Y intercept is to substitute in
X equals 0. It doesn't matter
what form the equation is in when
you start doing that process.

What you're going to end up with is two
different points on the two different
axes and all you need to do
is connect them using a ruler.

So if you guys get used to using all three
of these methods you'll get better
at being able to tell which method
is the best and the most efficient
for any given problem.