Linear Functions Flashcards
8 cards from real Bluebook SAT Test practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 8 Linear Functions flashcards as text
The equation y = −4x + 20 represents the remaining battery percentage of a phone x hours after charging stops. When will the battery reach 0%?
Answer: 5 hours
0 = −4x + 20 → 4x = 20 → x = 5.
Two lines are defined by y = 2x + 5 and y = 2x − 3. Which of the following is true?
Answer: They are parallel and never intersect
Both have slope 2 but different y-intercepts (5 and −3), so they are parallel.
A linear function f has the property that f(x + 2) − f(x) = 10 for all x. What is the slope of f?
Answer: 5
f(x+2)−f(x) = m(x+2)+b−(mx+b) = 2m = 10 → m = 5.
The data below models a linear pattern. What is the missing y value? x: 3, 6, 9, 12 | y: 7, 13, 19, ?
Answer: 25
Rate of change = (13−7)/(6−3) = 2; y increases by 6 every 3 units in x; y at x=12 is 19 + 6 = 25.
A caterer charges $200 as a flat fee plus $35 per guest. A client has a budget of $900. What is the maximum number of guests g they can invite?
Answer: 20
200 + 35g ≤ 900 → 35g ≤ 700 → g ≤ 20.
Line t has equation y − 3 = 2(x + 1). What is the y-intercept of line t?
Answer: 5
y − 3 = 2x + 2 → y = 2x + 5; y-intercept = 5.
If the linear function g passes through (0, −7) and (7, 0), what is the slope of g?
Answer: 1
Slope = (0 − (−7))/(7 − 0) = 7/7 = 1.
An electrician charges $90 for the first hour and $60 for each subsequent hour. After h hours total (h ≥ 1), which function gives the total bill B?
Answer: B(h) = 60h + 30
B = 90 + 60(h−1) = 90 + 60h − 60 = 60h + 30.