ShmoopTube

00:00

Slope Intercept Form, a la Shmoop. You work for the Mount Olympus Dept. of Eternal

00:10

Torture.

00:13

You need to design a torture device to Zeus' specifications...

00:17

... but all he's given you is a cryptic note that says "y equals three x plus four."

00:23

What in Hades does that mean?

00:26

You better figure this problem out fast, or you'll be up the river Styx without a paddle.

00:40

Praise Olympus. We're here to help.

00:42

Does the equation look familiar? It's written in slope-intercept form.

00:47

m is the slope of the line...

00:49

and b is the y-intercept...

00:51

Great, but what does that mean? Since we are given a point of the line, and

00:57

the slope...

00:59

... we can find an infinite number of other points on the line and connect them.

01:09

Remember that slope (m) is equal to the change in y divided by the change in x.

01:19

Slope = "rise over run." The slope-intercept form of a line is written

01:26

out as y equals mx + b How do we graph this to Zeus' specifications?

01:37

Let's examine how to graph one of these equations: y = 3x + 4.

01:42

We know that the number in front of x is the slope, three, and that 4 is the y-intercept.

01:52

Well get this done before Cerberus intercepts you for dinner.

01:59

Start by plotting the y-intercept, which is four.

02:02

You'll put a dot at four on the y-axis, which is the vertical one.

02:07

Next, since we know that the slope is three, also known as three over one...

02:11

...we know that another point will be three up and one over... in the positive direction

02:16

of course...

02:17

Here's how you would graph this point on your scroll.

02:19

Finally, connect these points. It's like connect-the-dots, torture edition.

02:26

There you have it.

02:27

If you think this problem was torture, just be glad you're not pushing a boulder up that

02:31

slope for all eternity.

Full Transcript