Bluebook SAT Test Linear Functions 2

Question 1

A gym membership costs $50 to join and $20 per month. After how many months will the total cost equal $210?

Accepted Answer

7

Answer

50 + 20m = 210 → 20m = 160 → m = 8... wait: 50 + 20(8) = 210. Let me recount: 20m = 160, m = 8.

Question 2

What is the slope of the line passing through (−3, 4) and (5, −4)?

Accepted Answer

−1

Answer

Slope = (−4 − 4)/(5 − (−3)) = −8/8 = −1.

Question 3

The graph of a linear function passes through (0, −3) and has slope 4. Which equation represents this function?

Accepted Answer

y = 4x − 3

Answer

With slope 4 and y-intercept −3, the equation in slope-intercept form is y = 4x − 3.

Question 4

A plumber charges $80 for the first hour and $55 for each additional hour. Which function gives the total charge T(h) for h hours (h ≥ 1)?

Accepted Answer

T(h) = 55(h − 1) + 80

Answer

The first hour costs $80, and each hour after that costs $55, so T(h) = 55(h − 1) + 80.

Question 5

If the slope of a line is 0, which of the following best describes the line?

Accepted Answer

The line is horizontal

Answer

A slope of 0 means no vertical change per unit of horizontal change, making the line horizontal.

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