Bluebook SAT Test Linear Functions 15

Question 1

Which of the following equations represents a linear function?

Accepted Answer

y = 3x + 2

Answer

y = 3x + 2 is the only equation of the form y = mx + b, making it linear.

Question 2

The function R(x) = −2x + 14 models the remaining miles x days into a road trip. On what day will 4 miles remain?

Accepted Answer

5

Answer

−2x + 14 = 4 → −2x = −10 → x = 5.

Question 3

A linear function f has the equation f(x) = px − 8. If f(4) = 4, what is the value of p?

Accepted Answer

3

Answer

4p − 8 = 4 → 4p = 12 → p = 3.

Question 4

Line m passes through (2, 5) and is perpendicular to a line with slope −1/3. What is the equation of m?

Accepted Answer

y = 3x − 1

Answer

Perpendicular slope = 3; using (2, 5): 5 = 3(2) + b → b = −1; y = 3x − 1.

Question 5

The points (1, a) and (4, 13) lie on a line with slope 2. What is the value of a?

Accepted Answer

7

Answer

(13 − a)/(4 − 1) = 2 → 13 − a = 6 → a = 7.

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