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CAHSEE Math 1.5 Algebra I 269 Views
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Description:
CAHSEE Math 1.5 Algebra I. Find the solution to the absolute value inequality.
Transcript
- 00:03
One un-a-shmoopy question a-comin’ a-right up!
- 00:07
The solution to the absolute value inequality… the absolute value of x minus 3 is less than 7 is… what?
- 00:14
And here are the potential answers…
- 00:19
So… what is this question asking?
- 00:21
Ooh – we have a few things going on here – absolute value and inequalities….
Full Transcript
- 00:27
We have to put numbers on either side of our variable… so we have a range for x.
- 00:33
We really have 2 equations we’re solving here as with any absolute value problem…
- 00:38
and we start with the rosy, positive one.
- 00:41
First assume that the absolute value things don’t exist… and it’s just the quantity
- 00:44
x minus 3 is less than 7.
- 00:47
So we add 3 to both sides to get x is less than 10. We know 10 is on the end… and we
- 00:52
can cross out A or B as potential answers.
- 00:55
But now let’s think about how we solve for the LESS THAN part of the equation.
- 01:00
We need to flip the little “greater than” thingy here – how do we do that?
- 01:04
We multiply by a negative number – in this case… negative 1.
- 01:07
So think about it as negative 1 times the quantity x minus 3… all now GREATER than 7.
- 01:13
We get negative x plus 3 is greater than 7…
- 01:17
Subtract 3 from both sides to get negative x is greater than 4…
- 01:21
…then divide both sides by negative one to get x is greater than negative 4…
- 01:26
So our answer is C.
- 01:27
As in, “Claustrophobia.”
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