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A Wide Absolute Value

Part of the Inequalities & Absolute Value section of Coddy's Algebra journey. Lesson 59 of 61.

Take ∣3x−6∣≤9\left|3x-6\right| \le 9. The sign is "less than or equal to", so the absolute value becomes a chain. Then do two steps on all three parts.

−9≤3x−6≤9-9 \le 3x-6 \le 9

−3≤3x≤15-3 \le 3x \le 15

−1≤x≤5-1 \le x \le 5

The condition says that 3x−63x-6 is within 9 of zero. For xx itself, this means within 3 of 2, so the solution is the segment from -1 to 5.

First get the absolute value bars alone on one side. Here they already are. Then look at the sign. A "less than" gives a chain, and a "greater than" gives two cases joined by "or". After the split, the steps are the same as for any chain or any pair of inequalities.

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Challenge

Hard

Solve the inequality ∣2x+2∣<8\left|2x+2\right| < 8 for xx.

Try it yourself

∣2x+2∣<8\left|2x+2\right| < 8

Get xx alone on one side

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