Algebra 1 Practice Test: Function Notation, Domain and Range
- Functions, Domain and Range
- 10 questions
- 13 minutes
These 10 questions cover evaluating f(x), reading what a function value means and finding domain and range. Tip: for the domain, ask which x-values would make the expression undefined.
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Question 1
If f(x) = 3x − 5, what is f(−2)?
Correct answer: B
Replace x with −2: 3(−2) − 5 = −6 − 5 = −11. Getting −1 comes from adding 5 instead of subtracting it.
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Question 2
Which relation is not a function?
Correct answer: D
In a function each input has exactly one output. Here the input 1 is paired with both 2 and 5. Repeated outputs, as in the first set, are allowed.
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Question 3
What is the domain of f(x) = x − 4?
Correct answer: A
The expression under a square root cannot be negative, so x − 4 ≥ 0 and x ≥ 4. The value 4 itself is allowed because 0 = 0.
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Question 4
What is the range of y = x2 + 3?
Correct answer: C
Since x2 is never negative, the smallest value of x2 + 3 is 3 (at x = 0), and the outputs grow without bound. So the range is y ≥ 3.
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Question 5
If g(x) = x2 − 2x, which expression equals g(a + 1)?
Correct answer: B
(a + 1)2 − 2(a + 1) = a2 + 2a + 1 − 2a − 2 = a2 − 1. The trap a2 − 2a + 1 is g(a) + 1, not g(a + 1).
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Question 6
If f(x) = 2x + 7, for what value of x is f(x) = 19?
Correct answer: A
Solve 2x + 7 = 19: 2x = 12, so x = 6. The value 45 is f(19), which answers a different question.
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Question 7
A climbing gym charges a $25 sign-up fee plus $15 per month. The total cost is C(m) = 25 + 15m, where m is the number of months.
What does C(6) = 115 mean?
Correct answer: D
The input m = 6 is the number of months and the output 115 is the total cost in dollars: 25 + 15(6) = 115.
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Question 8
What is the domain of h(x) = 5x + 3?
Correct answer: D
Division by zero is undefined, and x + 3 = 0 when x = −3. Every other real number works, including values less than −3.
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Question 9
What is the range of f(x) = −|x| + 4?
Correct answer: A
|x| is never negative, so −|x| is at most 0 and −|x| + 4 is at most 4. The graph is an upside-down V with its highest point at (0, 4).
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Question 10
A function is given by the set {(−3, 4), (0, 4), (2, −1), (5, 7)}. What is its domain?
Correct answer: B
The domain is the set of first coordinates (inputs). The set {−1, 4, 7} lists the outputs, which is the range.
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