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CAHSEE Math 1.5 Number Sense 190 Views
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Description:
Number Sense: Drill Set 1, Problem 5. Which of the following is equivalent?
Transcript
- 00:03
Here's a boring, unshmoopy question you'll find on the exam...
- 00:06
Which of the following is equivalent to negative 3 times one-half minus one-third times 2 to the fourth?
- 00:14
And here are the potential answers...
- 00:18
Lots of curveballs being thrown at your head here.
- 00:20
You can either panic... Or you can just break the problem into smaller
Full Transcript
- 00:23
parts and solve 'em one by one. Like this.
- 00:26
So... powers are top priority -- even ahead of multiplication and division...
- 00:30
...so let's get rid of that 'to the 4th' thing first.
- 00:34
Two times two is 4 times 2 is 8 times 2 is 16...
- 00:38
...so 2 to the 4th is 16. Onward and upward.
- 00:41
Now we should factor in the negative 3 so we can get rid of this set of parentheses.
- 00:45
And if we distribute that ugly negative 3
- 00:47
we get negative 3 times a half is negative 3 over 2 ... minus ... negative 3 over 3.
- 00:53
Luckily 3 over 3 is the same as 1 over 1... and since we're subtracting a negative,
- 00:57
we're really just adding a positive 1. We want our denominators to be the same, so
- 01:02
we'll rewrite 1 as 2 over 2...
- 01:04
...and adding them together we now have negative 3 over 2 plus
- 01:07
2 over 2 equals... negative one-half.
- 01:11
Let's not forget our 16... we still have
- 01:13
to find the product of that and our negative one-half...
- 01:16
Negative one-half times 16 equals negative sixteen halves... or negative 8.
- 01:21
Looks like our final answer is negative 8... which is option A.
- 01:25
So much prettier than what we started with. It's like we got a makeover.
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