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## Operations and Algebraic Thinking 222-226

### Unit 2: Lesson 3

Interpreting linear expressions- Interpreting linear expressions: diamonds
- Interpreting linear expressions: flowers
- Interpreting linear expressions
- Writing expressions word problems
- Writing expressions word problems
- Interpreting negative number statements
- Interpret negative number addition and subtraction expressions

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# Interpreting linear expressions: diamonds

We match the expressions to their meaning in this example. We're reinforcing our knowledge of linear expressions. Created by Sal Khan.

## Want to join the conversation?

- I'm confused. why is there more then one way to do a problem. so annoying.(0 votes)
- See the problem has different methods because later on you will be using that method and adding on to that for like calculus. Take cross multiplacation for instance you can do the ratio method but then when you go to calculus you wont be able to use the ration method only the cross multiplication method will work.(3 votes)

- At1:34, when Sal put the three other tiles into the "not used" section, one tile was 0.75p. This made me think that another way to solve the total bill could have been 2p-0.75p. That would have simplified to 1.25p. Is my way of thinking also applicable to the problem?(5 votes)
- What does 2P - .75p mean? 2P would be the cost of two ponies, and then you would have had to add 25% tax so that would be 2P(.25) = .50P, so cost of 2 ponies would be 2.50P, divide by 2 to get 1 to be 1.25P. .75P has no meaning within the context of the problem that I can figure out.(6 votes)

- When Khan Academy makes a Borderlands reference(2 votes)
- seriously, i am losing my mind right now(10 votes)

- This unlearns everything I learnt in elementary(4 votes)
- What did you learn in elementary? There is no such thing as a pony made of diamonds?(1 vote)

- how did jack afford the diamond horse?(4 votes)
- so if the tax so impotent why did they just do nothing(3 votes)
- 'Cause it's Khan Academy!(2 votes)

- what does this mean and can any one explain it differently??(3 votes)
- does anyone know how to switch ur avatar lol 😂😂😂(3 votes)
- Why is handsom jack buying a pony made out of diamonds(2 votes)
- Because then he could brag to his friends about having something so expensive.(2 votes)

- How can you tell if an expression or equation is linear without graphing it?(2 votes)
- An expression or equation (such as y equals a function of x) is linear if x is not raised to any power (or, equivalently, x is raised to the first power). The variable x can be multiplied by a scalar (such as 3x or -7.2x), and you can add a scalar to x (such as x + 4 or x - 0.6), and still be a linear function.

If x is raised to a power higher than one, then the expression or equation is not linear.(1 vote)

## Video transcript

Handsome Jack is buying
a pony made of diamonds. The price of the
pony is P dollars. And Jack also has to pay
a 25% diamond pony tax. Match the expressions to their
meaning for Handsome Jack. And they say
multiple expressions may fit the same description. So in this bucket, we have
the price of the diamond pony before tax. Well, they already tell us that
the price of the diamond pony is P dollars. So that's P right over here. Now over here, they say the
amount of tax Handsome Jack pays. Well, he pays a 25%
diamond pony tax. So whatever the price is,
he's going to pay 25% of that. Or another way of
thinking about it, he's going to pay 25% is
the same thing as 0.25. So 0.25 times P is
the amount of tax he's going to pay on
this diamond pony. Now, they say Handsome
Jack's total bill for the diamond pony. Well, he's going to pay P for
the pony plus 0.25P in taxes. So that is this one
right over here. P for the pony plus
0.25P for the taxes. So that's that one over there. But if we look at this, you
could view this literally as 1P plus 0.25P's. Well, that's the
same thing as 1.25P. So that's the same thing
as this right over here. So it's 1.25P. And these other three
don't seem to fit in any of these categories. So I'm going to put
it into the not used. We're required to
categorize everything. So let me put this
in the not used. It's falling off the
screen, I realize. Let me put this in the not used. And then let me put
this in the not used. Let's check our answer. We got it right.