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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 2.2 Algebra and Functions 303 Views
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Description:
SAT Math 2.2 Algebra and Functions. What value of y is correct?
Transcript
- 00:02
Put this in your calculator and shmoop it...
- 00:05
If x to the y power... to the y power... to the y power...
- 00:10
to the y power... equals x to the 81st power... then y can be which of the following?
- 00:17
And here are the potential answers...
- 00:23
There may be a lot of parentheses here, but don't panic.
Full Transcript
- 00:25
All we need is a simple exponent rule. Remember this rule?
- 00:31
When we take an exponent to an exponent, all we have to do is multiply the two exponents together.
- 00:38
So x to the y to the y is the same thing as x to the y squared.
- 00:44
So x to the y squared to the y to the y is the same thing as x to the y to the fourth power.
- 00:53
The base of both sides are the same, so the exponents of both sides must be the same.
- 01:00
Yeah, probably.
- 01:01
So y to the fourth is equal to 81.
- 01:03
What number, to the fourth power, is 81?
- 01:06
Well, 3 times 3 is 9 times 3 is 27 times 3 is 81, but
- 01:10
3 isn't the only number that's equals 81 when raised
- 01:14
to the fourth power. What's another one that works?
- 01:18
Negative 3 to the fourth power is also 81.
- 01:21
The negative cancels out since the exponent is even.
- 01:25
So yep, E is our answer.
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