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Course: Digital SAT Math > Unit 4
Lesson 6: Isolating quantities: foundationsIsolating quantities | Lesson
A guide to isolating quantities on the digital SAT
What are isolating quantities problems?
Many real-world scenarios can be described using equations and formulas with multiple variables. For example, the formula for the area,
If we want to find the equivalent equation, but with
You can learn anything. Let's do this!
How do I isolate quantities?
Manipulating formulas: temperature
Like solving equations, but with more variables
Isolating quantities is similar to solving equations. However, instead of ending up with a variable equal to a constant, we end up with a variable equal to an expression containing other variables. In fact, if you've rewritten a linear equation like
The most important thing to remember is that the rearranged equation will remain equivalent to the original equation only if we always treat both sides equally: whenever we do something to one side, we must do the exact same thing to the other side.
To isolate a quantity in an equation or formula:
- Write down the original equation. If needed, translate the word problem or given context into an equation.
- Perform the same operation on both sides of the equation to begin isolating the desired quantity.
- Repeat Step 2 until the desired quantity is isolated.
Let's look at some examples!
A physics student uses the formula
The distance
Try it!
Your turn!
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Finally something easy after so many hard topics(200 votes)- my first thought(20 votes)
- I can't believe that this is a separate unit(74 votes)
There are a few reasons its separate. First of all, it makes it easier for people to find it and bookmark it. Second, it helps Khans reputation and gets them more customers if they have a unit for SAT prep so that they can point it out.(2 votes)
- why math section is classified into three level: foundation, Medium and advance ? although there is a same question and same explanation?(31 votes)
the practice questions are different for each level, you gotta check them out(55 votes)
This was very basic and covered in previous lessons. I dont see the point of adding this(17 votes)- will they give us the formulas in the questions? Like should I memorize the C to F formula?(7 votes)
Of course not, this is a math exam, not physics, so you only have to memorize math formulas(12 votes)
I thought this was far easier but also taught very well.(7 votes)- lo único que aprendi de física fue a despejar(5 votes)
This is part of the advanced math section??(2 votes)- Yes, its with advanced math because people usually think of SATs as hard. Also because its normally only found in higher grade levels.(1 vote)
- Why don't they just use transposition for these questions?(1 vote)
- how do you know when the sign changes if it is originally positive or negative(1 vote)
the same changes you do on right you also do on left, or reciprocal. So, what you do on a side, you repeat it on the another side, for example if you add/multiply 4 on the left side, you do that also to the right side(1 vote)