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SAT Math Videos 171 videos
SAT Math 1.1 Statistics and Probability. In which of the following data sets are the arithmetic mean and the median equal?
SAT Math: Statistics and Probability Drill 1, Problem 2. If the four largest numbers in the set were doubled, what would happen to the median...
SAT Math 1.3 Statistics and Probability. Approximately what is the probability that they will be placed in alphabetical order?
SAT Math 4.5 Algebra and Functions 208 Views
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Description:
SAT Math 4.5 Algebra and Functions
Transcript
- 00:02
Here’s your shmoop du jour, brought to you by Dollar Signs.
- 00:05
Why can’t there be more of THOSE on the highway?
- 00:08
If x $ y is defined as x $ y equals the square root of x squared minus y squared,
- 00:18
and 13 $ y = 5, what is y?
- 00:22
And here are the potential answers…
Full Transcript
- 00:26
Is it just us are you seeing dollar signs?
- 00:29
So we're given that x $ y equals the square root of x squared minus y squared.
- 00:34
So, 13 $ y is the square root of 13 squared minus y squared.
- 00:43
The given information tells us that 13 $ y equals 5.
- 00:47
This can be written as the equation square root of 13 squared minus y squared equals 5.
- 00:53
This gives us square root of 169 minus y squared equals 5.
- 00:59
Let’s get rid of the square root by squaring both sides.
- 01:02
This gives us 169 minus y squared equals 25.
- 01:07
We add y squared to both sides, then subtract 25 from both sides to get 144 equals y squared.
- 01:14
Now we can take the square root of 144 to get y equals 12.
- 01:18
BUT…we have to remember that negative 12 is also an answer, since a negative, when
- 01:23
squared, is positive.
- 01:24
The answer is (E).
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