2003 AMC 12B Problem 9

Below is the professionally curated solution for Problem 9 of the 2003 AMC 12B, from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2003 AMC 12B solutions, or check the answer key.

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Concepts:slopelinear equation

Difficulty rating: 1040

9.

Let ff be a linear function for which f(6)f(2)=12.f(6) - f(2) = 12. What is f(12)f(2)?f(12) - f(2)?

1212

1818

2424

3030

3636

Solution:

The slope of ff is f(6)f(2)62=124=3. \frac{f(6) - f(2)}{6 - 2} = \frac{12}{4} = 3.

Therefore f(12)f(2)=3(122)=30. f(12) - f(2) = 3(12 - 2) = 30.

Thus, the correct answer is D.

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