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Zorluk: KolayIntegers, Absolute Value, and Number Lines

On a standard number line, the distance between two points, AA and BB, is 1212 units. If the coordinate of point AA is −18-18, which of the following is a possible coordinate for point BB?

  1. −30-30Cevap
  2. B
    −12-12
  3. C
    −8-8
  4. D
    66
  5. E
    3030

Cevap

−30-30
The correct answer is −30-30 because the distance between two points on a number line is found by taking the absolute value of the difference between their coordinates. Setting up the relation ∣b−(−18)∣=12|b - (-18)| = 12 simplifies to ∣b+18∣=12|b + 18| = 12. Solving this absolute value equation yields two possible locations: b+18=12b + 18 = 12 (which gives b=−6b = -6) and b+18=−12b + 18 = -12 (which gives b=−30b = -30). Among the choices, −30-30 is the only possible coordinate listed.

Adım Adım Çözüm

1
Set up the absolute value equation representing the distance between point A and point B on the number line.
Let bb be the coordinate of point BB. The distance between AA and BB is given by ∣−18−b∣=12|-18 - b| = 12.
On a standard number line, the distance between any two coordinates xx and yy is given by the absolute value of their difference, ∣x−y∣|x - y|.
2
Solve the absolute value equation for the two possible cases.
Case 1: −18−b=12⇒−b=30⇒b=−30-18 - b = 12 \Rightarrow -b = 30 \Rightarrow b = -30. Case 2: −18−b=−12⇒−b=6⇒b=−6-18 - b = -12 \Rightarrow -b = 6 \Rightarrow b = -6.
An equation of the form ∣x∣=d|x| = d (where d≥0d \geq 0) splits into two distinct equations: x=dx = d and x=−dx = -d.
3
Compare the possible solutions with the given options.
The value −30-30 is one of the possible coordinates and is listed in the options.
To identify which of the two mathematically correct coordinates (-30 or -6) is provided as an answer choice.

Anahtar Kavram

The distance between two points on a number line with coordinates xx and yy is represented by the absolute value of their difference, ∣x−y∣|x - y|.
Tahmini Süre:45s
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