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Pre-Algebra Videos 34 videos

ACT Math 5.2 Pre-Algebra
1939 Views

ACT Math: Pre-Algebra Drill 5, Problem 2. If a and b are prime numbers, how many factors does ab have?

ACT Math 1.2 Pre-Algebra
891 Views

ACT Math: Pre-Algebra Drill 1.2. What proportion of Jenna's day is spent Wii-swimming?

ACT Math 1.1 Pre-Algebra
1061 Views

Pre-Algebra Drill 1, Problem 1. Calculate 23 + 53(7 – 4).

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ACT Math 2.2 Pre-Algebra 421 Views


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Description:

ACT Math Pre-Algebra: Drill 2, Problem 2. Solve for y.

Language:
English Language

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

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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