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ACT Math: Pre-Algebra Drill 5, Problem 2. If a and b are prime numbers, how many factors does ab have?
ACT Math 2.2 Pre-Algebra 421 Views
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Description:
ACT Math Pre-Algebra: Drill 2, Problem 2. Solve for y.
Transcript
- 00:03
Here's a question you can really shmoop to...
- 00:07
Solve for y: 100 over y minus 16 equals 40. And here are the potential answers...
- 00:16
OK, what's this fine problem asking us to do?
- 00:18
Eh. It's a pretty vanilla test to see if we can handle a variable in the denominator.
- 00:24
So... first things first -- let's simplify a bit and add 16 to both sides... to get 100
Full Transcript
- 00:30
over y equals 56.
- 00:33
Now let's get that twisted denominator y on top as a numerator, and multiply both sides
- 00:38
by y... to get 100y over y equals 56y.
- 00:43
Why? Because we said so.
- 00:45
So that's 100y on the left and 56y on the right
- 00:48
Divide both sides by 56 and we have y equals 100 over 56.
- 00:53
Now time to reduce. Thank you, Curves.
- 00:56
Both numbers are even, so we know we can divide by 2... which gives us 50 over 28.
- 01:01
Whoops... still even. So divide by 2 again and we have 25 over 14.
- 01:05
Boom. The answer is D.
- 01:07
As in, "Dangerous denominators."
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