Bluebook SAT Test Linear Functions 3

Question 1

A line with equation y = kx − 4 passes through the point (3, 8). What is the value of k?

Accepted Answer

4

Answer

Substitute (3, 8): 8 = 3k − 4 → 3k = 12 → k = 4.

Question 2

The rate of change of a linear function is 5 and f(2) = 11. What is f(0)?

Accepted Answer

1

Answer

f(x) = 5x + b; 11 = 5(2) + b → b = 1, so f(0) = 1.

Question 3

Line p is parallel to the line y = 3x − 7 and passes through (1, 2). What is the equation of line p?

Accepted Answer

y = 3x − 1

Answer

Parallel lines have equal slopes; using slope 3 and point (1, 2): 2 = 3(1) + b → b = −1, so y = 3x − 1.

Question 4

A cell phone plan charges a monthly base fee of $25 plus $0.10 per text message. If a customer's bill is $37, how many text messages did they send?

Accepted Answer

120

Answer

25 + 0.10t = 37 → 0.10t = 12 → t = 120 text messages.

Question 5

The graph below has a y-intercept of 4 and passes through (2, 0). What is the slope of the line?

Accepted Answer

−2

Answer

Slope = (0 − 4)/(2 − 0) = −4/2 = −2.

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