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
Line s passes through (−4, 3) and (0, −1). What is the equation of line s?
Answer: y = −x − 1
Slope = (−1 − 3)/(0 − (−4)) = −4/4 = −1; y-intercept = −1, so y = −x − 1.
A linear model predicts that every additional hour of study increases a test score by 4 points, starting from a base of 58. Which equation represents score S after h hours?
Answer: S = 4h + 58
The rate of increase is 4 per hour (slope = 4) and the initial score is 58 (y-intercept), giving S = 4h + 58.
If f(3) = 11 and the rate of change is −3, what is f(6)?
Answer: 2
From x = 3 to x = 6 is 3 steps; f(6) = 11 + 3(−3) = 11 − 9 = 2.
Which line has an undefined slope?
Answer: x = 7
A vertical line such as x = 7 has undefined slope because the change in x is zero.
The function P(w) = 80w − 320 gives weekly profit P in dollars when w workers are employed. How many workers are needed to break even?
Answer: 4
P(w) = 0 → 80w = 320 → w = 4.
A line has a slope of 2/5 and passes through (5, 4). What is the y-intercept?
Answer: 2
4 = (2/5)(5) + b → 4 = 2 + b → b = 2.
At time t = 0, a train is 15 miles from a station. It travels away at 60 mph. Which function gives its distance D from the station?
Answer: D(t) = 60t + 15
Starting 15 miles away and moving at 60 mph further away: D(t) = 60t + 15.
What is the value of k if the points (k, 1) and (3, 7) lie on a line with slope 3?
Answer: 1
Slope = (7 − 1)/(3 − k) = 3 → 6 = 3(3 − k) → 6 = 9 − 3k → 3k = 3 → k = 1.