Regarding number properties book and absolute value
Problem #16 pg 75
why is the solution abs value of x+4 and not abs value of x-4?
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- mobenny
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Re: NP pg 75 #16
There are a number of different ways to think about this.
First, you could just think about the different end points: -7 and -1. When you add 4 to -7, you get -3, which has an absolute value of 3, a match. Ditto for -1. Add 4 to -1 and you get 3, which has an absolute value of 3 as well.
Another way to think about it is that the midpoint of the range is -4. The endpoints extend some amount beyond that. Take a look at pages 112-113 in the EIV book (strategy guide #3) for and explanation of Inequalities and Absolute Value that will allow you to apply these concepts more generally.
First, you could just think about the different end points: -7 and -1. When you add 4 to -7, you get -3, which has an absolute value of 3, a match. Ditto for -1. Add 4 to -1 and you get 3, which has an absolute value of 3 as well.
Another way to think about it is that the midpoint of the range is -4. The endpoints extend some amount beyond that. Take a look at pages 112-113 in the EIV book (strategy guide #3) for and explanation of Inequalities and Absolute Value that will allow you to apply these concepts more generally.
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