Bluebook SAT Test Linear Functions 12

Question 1

The line 2y = 6x − 10 is graphed. What are the slope and y-intercept?

Accepted Answer

slope = 3, y-intercept = −5

Answer

Divide by 2: y = 3x − 5; slope = 3, y-intercept = −5.

Question 2

A linear function has the values shown: f(−2) = 8 and f(4) = −4. What is f(1)?

Accepted Answer

2

Answer

Slope = (−4 − 8)/(4 − (−2)) = −12/6 = −2; f(x) = −2x + b; f(−2) = 8 → b = 4; f(1) = −2 + 4 = 2.

Question 3

A parking garage charges $4.00 for the first hour and $2.50 for each additional hour. Which function gives the total charge T for h hours (h ≥ 1)?

Accepted Answer

T(h) = 2.50(h − 1) + 4.00

Answer

For h ≥ 1, the cost is $4.00 for hour 1 plus $2.50 for each of the remaining (h − 1) hours: T = 2.50(h − 1) + 4.00.

Question 4

If the graph of y = kx − 6 passes through (3, 0), what is the value of k?

Accepted Answer

2

Answer

0 = k(3) − 6 → 3k = 6 → k = 2.

Question 5

Lines p and q are perpendicular. Line p has slope −5/2. What is the slope of line q?

Accepted Answer

2/5

Answer

The perpendicular slope is the negative reciprocal: −1/(−5/2) = 2/5.

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