CAASPP Functions 2 — Questions and Answers
Question 1: What is the y-intercept of the function f(x) = 4x − 9?
- 4
- −4
- 9
- −9 (Correct answer)
Correct answer: −9
The y-intercept is the value of b in f(x) = mx + b; here b = −9, confirmed by evaluating f(0) = 4(0) − 9 = −9.
Question 2: Which equation models exponential growth?
- y = 2x + 1
- y = x²
- y = 2^x (Correct answer)
- y = 2/x
Correct answer: y = 2^x
y = 2^x is exponential because the variable x appears as an exponent, causing the output to double with each unit increase in x.
Question 3: If f(x) = x² + 2, what is f(−3)?
- −7
- 7
- 11 (Correct answer)
- −11
Correct answer: 11
f(−3) = (−3)² + 2 = 9 + 2 = 11.
Question 4: Which statement best describes the rate of change of a linear function?
- It increases, then decreases
- It is always zero
- It is constant (Correct answer)
- It varies depending on x
Correct answer: It is constant
Linear functions have a constant rate of change (slope), which is the defining characteristic that distinguishes them from non-linear functions.
Question 5: A function has the equation y = 3x. If x doubles, what happens to y?
- y stays the same
- y triples
- y doubles (Correct answer)
- y is halved
Correct answer: y doubles
Since y = 3x, if x becomes 2x then y = 3(2x) = 2(3x), so y also doubles.
Question 6: What does the domain of a function represent?
- All possible output values
- All possible input values (Correct answer)
- The rate of change of the function
- The y-intercept of the function
Correct answer: All possible input values
The domain is the complete set of possible input values (x-values) for which the function is defined.
Question 7: Which of the following functions has the greatest rate of change (steepest slope)?
- f(x) = x + 5
- f(x) = 3x − 1
- f(x) = −4x + 2 (Correct answer)
- f(x) = 2x − 7
Correct answer: f(x) = −4x + 2
The rate of change is the absolute value of the slope; |−4| = 4 is the greatest among 1, 3, 4, and 2.
CAASPP Functions 2
What is the y-intercept of the function f(x) = 4x − 9?