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Solve the inequality |8x + 4| <28
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2 Answers

3 votes

Answer:

4<x< 3

Explanation:

User Joanis
by
8.2k points
5 votes

The absolute value
|x| always returns the "positive version" of a number.

This means that if the number is positive, the absolute value does nothing:


|x| = x

And if the number is negative, the absolute value flips its sign:


|x| = -x

So, if 8x+4 is positive, the inequality becomes


8x+4 < 28

If 8x+4 is negative, the inequality becomes


-8x-4 < 28 \iff 8x+4 > -28

So, 8x+4 must be either a positive number smaller than 28, or a negative number greater than -28. It means that


-28 < 8x+4 < 28

Subtract 4 from all sides:


-32 < 8x < 24

Divide all sides by 8:


-4 < x < 3

User Ton Snoei
by
8.9k points