Why do you distribute the 3 to only one side?

you don't . you have to do it to both sides

I'm not understanding WHY he's distributing the 3...Anyone mind explaining this?

That's just how Steven chose to solve the problem, probably because it's easier to visualize the problem that way. Alternatively, you could divide both sides by 3 in step one, resulting in 2x = x + 4. Then it's just a matter of subtracting x on both sides, resulting in x = 4.

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Class 10 (Foundation)

Course: Class 10 (Foundation) > Unit 4

Lesson 1: Equations in 1 variable

Figuring out missing algebraic step

Name: Figuring out missing algebraic step
Uploaded: 2014-02-02T07:25:45Z
Description: There is a hidden step in Steven's solution to solving an equation. There are different ways to solve an equation. To find Steven's missing step, we can see what we would do in the equation. Then we can see if another step will get us to the work Sten is showing. If not, we can try solving a different way.

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There is a hidden step in Steven's solution to solving an equation. There are different ways to solve an equation. To find Steven's missing step, we can see what we would do in the equation. Then we can see if another step will get us to the work Sten is showing. If not, we can try solving a different way. Created by Sal Khan.

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Aeatchan
Posted 8 years ago. Direct link to Aeatchan's post “I find it interesting tha...”
I find it interesting that the equation:
x/3+2=7
When started by multiplying both sides by three
and then subtracting both sides by 2 will give a result of:
X=19
However, when solving it by subtracting both sides by two and then multiplying both sides by three the result will be X=15.
I will always keep this in mind when solving equations from now on.
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(3 votes)
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kimi
Posted 7 years ago. Direct link to kimi's post “Why do you distribute the...”
Why do you distribute the 3 to only one side?
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(2 votes)
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- alex.buhl
  Posted 7 years ago. Direct link to alex.buhl's post “you don't . you have to d...”
  you don't . you have to do it to both sides
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  (2 votes)
LaTosha
Posted 8 years ago. Direct link to LaTosha's post “Which number is <197 and ...”
Which number is <197 and >97?
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(2 votes)
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- Justyna S
  Posted 8 years ago. Direct link to Justyna S's post “Any number that is less t...”
  Any number that is less than 197 and greater than 97. For example 100, 148, 179, etc. It can also be a fraction or decimal such as 97.0000001, 196.9999, 105.5, 105/1000, etc.
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  (0 votes)
Mujahid
Posted 8 years ago. Direct link to Mujahid's post “I'm not understanding WHY...”
I'm not understanding WHY he's distributing the 3...Anyone mind explaining this?
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(1 vote)
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- david.dreis
  Posted 8 years ago. Direct link to david.dreis's post “That's just how Steven ch...”
  That's just how Steven chose to solve the problem, probably because it's easier to visualize the problem that way. Alternatively, you could divide both sides by 3 in step one, resulting in 2x = x + 4. Then it's just a matter of subtracting x on both sides, resulting in x = 4.
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  (2 votes)
praveenya33
Posted 3 years ago. Direct link to praveenya33's post “How do you solve the equa...”
How do you solve the equation (39/3)+n?
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(1 vote)
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- Kim Seidel
  Posted 3 years ago. Direct link to Kim Seidel's post “You don't have an equatio...”
  You don't have an equation. So, you can't solve for "n". You have an algebraic expression. All you can do is reduce your fraction to simplify the expression.
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  (1 vote)
NotAlive
Posted 7 years ago. Direct link to NotAlive's post “Is it possible to figure ...”
Is it possible to figure out more than 2 steps at a time?
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(1 vote)
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VictoriaQueen5
Posted 7 years ago. Direct link to VictoriaQueen5's post “When it comes down to get...”
When it comes down to getting the x by itself, how do you know whether to add, subtract, multiply or divide the number next to the x?? I am a little confused.
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(1 vote)
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Meyer
Posted 8 years ago. Direct link to Meyer 's post “how would u solve an equa...”
how would u solve an equation like this 5b+b=12
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(1 vote)
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- Paul Simon Castro
  Posted 8 years ago. Direct link to Paul Simon Castro's post “Combine like terms. 5b+(1...”
  Combine like terms. 5b+(1)b is equal to 6b. Now you have 6b=12. In order to have the variable "b" by itself, divide both sides by 6, and you should get b=2. :)
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  (1 vote)
Meyer
Posted 8 years ago. Direct link to Meyer 's post “how do u answer a questio...”
how do u answer a question with 6x+7=5b how would u solve a problem like that
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(1 vote)
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- Bernard Rich
  Posted 7 years ago. Direct link to Bernard Rich's post “When I took college math ...”
  When I took college math I was told, "To find two unknowns you need two equations." So if you have only one equation with two variables, you can only find the value of one variable in terms of the other. You can divide both sides by 6 which will give you
  x + 7 / 6 = 5b / 6 and then subtract 7 / 6 from both sides giving
  x = (5b -7) / 6
  or divide both sides by 5 which will give you
  b = (6x + 7) / 5.
  b = (6x + 7) / 5.
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  (1 vote)
Ayodele Vaughan
Posted 5 years ago. Direct link to Ayodele Vaughan's post “how do you find the missi...”
how do you find the missing expression
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(1 vote)
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Video transcript

Voiceover:Below are the steps that Steven used to correctly solve the equation six X is equal to three times X plus four, four X. Step one is missing. What could Steven have written for step one? So let's see, so this is the original equation, they give us a blank for step one, and then we see that he eventually gets to three X equals 12. That he divides both sides by three and he gets to X equals four. So the best way I could think about doing this is to think, what would I do? Well if I saw something like this, my extinct would be to distribute this three so that I could start separating the parts of this expression that have a variable, that have the X, and the parts that are constant. So let's try to distribute this three and see what we get. and see if that's a reasonable step for the direction that Steven went in. So if we do that, we'd get six X is equal to, we haven't changed the left-hand side, and the right-hand side three times X is three X. Then three times four is 12. So you get six X is equal to three X plus 12. Now if I don't even look at what Steven's doing right over here, if I'm trying to solve for X, what would be the next thing that I would do? Well, I'd try to isolate all of the X's on one side, and if I want all the X's on the left-hand side I would subtract three X from both sides. So if you subtract three X from both sides you would then get Steven's second step right over here. So this looks like a completely reasonable first step for Steven. The first step is he distributes the three to get this expression, then he subtracts three X from both sides to get three X is equal to 12, and then he divides both sides by three to get X is equal to four.