ShmoopTube

00:04

Two-Step Equations using Addition and Subtraction, a la Shmoop. [Disco ball]

00:09

Darlo is your average foreign exchange student.

00:11

He hails from a country no one can pronounce, dresses like it’s 1978, and is hopelessly [Darlo holding his lunch tray]

00:17

in love with the wrong girl.

00:19

In a desperate attempt to win McKenzie’s heart, Darlo enters the Spring Talent Show. [Advert for the spring talent show stuck on some lockers]

00:24

Unfortunately, his only talent is…disco dancing. [Darlo starts disco dancing]

00:28

Darlo boogies away to the tune “Disco Love” three times…

00:33

…then dances for six minutes of “Dance Fever.” [Darlo dancing under spotlights]

00:36

If Darlo dances for a total of ten minutes before getting annihilated by McKenzie’s

00:41

big boyfriend…

00:42

…can you determine how long the song “Disco Love” is?

00:46

First we’ll need to find the variable. [McKenzie finds the variable hiding behind the sofa]

00:48

Since we want to solve for Disco Love’s length, we’ll make that our “x”.

00:52

Darlo dances “Disco Love” three times, so we’ll call the total time it took him

00:57

to dance that song… 3x.

00:59

Now we’ll add the six minutes he grooves to “Dance Fever.”

01:02

Darlo dances for a total of 10 minutes.

01:05

So… 3x + 6 = 10

01:07

To get all the x’s on one side, we can subtract 6 from both sides to get 3x equals 4.

01:16

Remember to make the same move on both sides of that equal sign to maintain equality. [Darlo appears doing a dance move on both sides of the equation]

01:21

To solve for x, we then divide both sides by 3.

01:24

3x divided by 3 equals x... so there you have it!

01:28

x equals four-thirds.

01:29

Or, expressed as a mixed number… [Darlo holds his hands up and looks unsure]

01:33

1 and 1/3 minutes.

01:34

To find 1/3 of a minute, we multiply 1/3 by 60, the number of seconds in a minute…

01:40

…or divide 60 by 3, to get 20. [Clock spinning round]

01:43

Which means that “Disco Love” is one minute and twenty seconds, uh… too long.

01:47

Darlo, next time you fall for a girl, make sure her boyfriend isn’t on the football [Darlo is chased by various sports teams]

01:50

team.

01:51

Or the basketball team.

01:52

Or the soccer team…

Full Transcript