Question

Difficulty: MediumIntegers, Absolute Value, and Number Lines

Let aa and bb be integers. On a standard number line, a=−14a = -14, and the distance between aa and bb is 2323. If b>0b > 0, what is the value of ∣2b−∣a∣∣|2b - |a||?

Answer: 4

Answer

The value of ∣2b−∣a∣∣|2b - |a|| is 4.
The distance between a=−14a = -14 and bb on the number line is ∣b−(−14)∣=∣b+14∣=23|b - (-14)| = |b + 14| = 23. Solving for a positive value of bb gives b+14=23b + 14 = 23, so b=9b = 9. The absolute value of aa is ∣−14∣=14|-14| = 14. Substituting these values into ∣2b−∣a∣∣|2b - |a|| yields ∣2(9)−14∣=∣18−14∣=4|2(9) - 14| = |18 - 14| = 4.

Step-by-Step Solution

1
Determine the value of integer bb using the distance relationship on the number line.
The distance formula ∣b−(−14)∣=23|b - (-14)| = 23 simplifies to ∣b+14∣=23|b + 14| = 23. Since b>0b > 0, b=9b = 9.
The distance between two points xx and yy on a number line is given by ∣x−y∣|x - y|.
2
Calculate the absolute value of aa.
∣a∣=∣−14∣=14|a| = |-14| = 14.
The absolute value of a negative number is its positive magnitude.
3
Substitute b=9b = 9 and ∣a∣=14|a| = 14 into the expression ∣2b−∣a∣∣|2b - |a||.
∣2(9)−14∣=∣18−14∣=4|2(9) - 14| = |18 - 14| = 4.
Perform operations inside the outer absolute value first, then take the absolute value of the result.

Key Concept

Absolute Value as Distance on a Number Line
Estimated Time:1m 0s
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