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Two-Step Equations Using Multiplication/Division 4115 Views
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Description:
This video helps you tackle two-step equations with multiplication and division by using the opposite operation on each side of the equation. Definitely less scary than laser sharks!
Transcript
- 00:04
Two-Step Equations Using Multiplication and Division , a la Shmoop.
- 00:12
After returning from vacation, Dr. Villain comes home to find he has only one laser-shark
- 00:17
left.
- 00:18
His man-servant, Bill, explains that the first half were killed by flesh-eating bacteria.
- 00:24
And then he ate another three because he'd forgotten to go grocery shopping.
Full Transcript
- 00:34
Can you determine how many sharks Dr. Villain had before his Jamaican getaway?
- 00:41
As always, we'd like to have a formula to help us solve the problem.
- 00:45
So we first need to determine the variable.
- 00:49
Because we're trying to figure out the original number of sharks, we're going to substitute
- 00:53
that value with x. In the beginning, there were x number of sharks.
- 00:59
Then half were eaten by flesh-eating bacteria. We'll write that as x over 2.
- 01:03
Guess someone should have washed their hands a little better.
- 01:11
Then Bill ate three of the sharks, so we'll subtract 3.
- 01:15
We know there was only one shark left, so we can put 1 to the right of the equals sign.
- 01:21
Our goal is to get x all by itself on one side. So let's first get rid of that pesky
- 01:26
-3.
- 01:27
We can do that by using the opposite operation and adding 3 to both sides.
- 01:34
Remember to always perform the same operation on both sides; Dr. Villain is fair that way.
- 01:40
Now we have x divided by 2 equals 4.
- 01:44
While we can't undo the near-extinction of the laser-shark, we can undo x being divided
- 01:49
by 2... by multiplying 2 to both sides. And there you have it, Villains and Man-Servants:
- 01:57
x equals 8.
- 02:01
Which means the original number of laser-sharks totaled 8.
- 02:06
Hey there, turn that frown upside down, Dr. Villain.
- 02:11
You may only have one laser-shark left. But even a sad, friendless laser-shark is still
- 02:16
a laser shark!
- 02:20
Just remember that, in the future, you might want to hire better help...preferably someone
- 02:24
who doesn't have a taste for laser shark.
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