Funções Practice Questions
ENEM (Brazil) · ENEM Matemática · 145 free MCQs with instant results and detailed explanations.
145
Total
44
Easy
72
Medium
29
Hard
Start Practicing Funções
Take a timed quiz or customize your practice session
Sample Questions from Funções
Here are 10 sample questions. Start a quiz to get randomized questions with scoring.
Q1
Easy
What is the value of f(2) if the function f(x) is defined as f(x) = 3x + 5?
A.
11
B.
10
C.
8
D.
7
Show Answer & Explanation
Correct Answer: A
To find f(2), substitute 2 for x in the function. f(2) = 3(2) + 5 = 6 + 5 = 11, so the correct answer is A.
Q2
Easy
What is the value of f(3) for the function f(x) = 2x + 1?
A.
7
B.
6
C.
5
D.
4
Show Answer & Explanation
Correct Answer: A
To find f(3), substitute x with 3 in the function: f(3) = 2(3) + 1 = 6 + 1 = 7.
Q3
Easy
Which of the following statements about the function h(x) = 3x - 5 is true?
A.
h(1) = -2
B.
h(2) = 1
C.
h(0) = -5
D.
h(3) = 4
Show Answer & Explanation
Correct Answer: C
To find h(0), substitute 0 into h(x): h(0) = 3(0) - 5 = 0 - 5 = -5, confirming option C.
Q4
Medium
What is the range of the function f(x) = -2x^2 + 8x - 3?
A.
[−∞, 10]
B.
[−∞, 5]
C.
[5, ∞)
D.
[10, ∞)
Show Answer & Explanation
Correct Answer: A
The function is a quadratic equation that opens downwards. To find the maximum value, we use the vertex formula. The x-coordinate of the vertex is given by -b/(2a), which gives us 2. Plugging x=2 into the function yields f(2) = 10, hence the range is [−∞, 10].
Q5
Medium
Which of the following statements about the function f(x) = x^2 + 4x + 3 is true?
A.
It has a maximum value.
B.
It has no real roots.
C.
It opens upwards.
D.
It is a linear function.
Show Answer & Explanation
Correct Answer: C
The function is a quadratic function with a positive leading coefficient (1). Hence, it opens upwards, which implies it has a minimum value, not a maximum. Therefore, the correct answer is C.
Q6
Medium
If g(x) = 2x + 5 and h(x) = x^2, what is (g ∘ h)(2)?
A.
9
B.
13
C.
17
D.
25
Show Answer & Explanation
Correct Answer: B
To calculate (g ∘ h)(2), we first find h(2) = 2^2 = 4. Then, we substitute this value into g: g(4) = 2(4) + 5 = 8 + 5 = 13. Thus, the correct answer is B.
Q7
Medium
What is the y-intercept of the function f(x) = -3x + 4?
A.
4
B.
3
C.
0
D.
-4
Show Answer & Explanation
Correct Answer: A
The y-intercept of a linear function is found by evaluating f(0). Substituting x = 0 into the function gives f(0) = -3(0) + 4 = 4. Therefore, the y-intercept is 4.
Q8
Hard
Consider the function f(x) = 2x^2 - 8x + 7. What is the minimum value of this quadratic function?
A.
1
B.
0
C.
3
D.
4
Show Answer & Explanation
Correct Answer: A
To find the minimum value of the quadratic function, we can use the vertex formula x = -b/(2a). Here, a=2 and b=-8, so x = 8/(4) = 2. Plugging x = 2 back into the function gives f(2) = 2(2)^2 - 8(2) + 7 = 8 - 16 + 7 = -1, which is the vertex's y-coordinate. Thus, the minimum value is 1.
Q9
Hard
Consider the function f(x) = 2x^2 - 8x + 6. What is the vertex of the parabola represented by this function?
A.
(2, -2)
B.
(4, -6)
C.
(2, -4)
D.
(4, -2)
Show Answer & Explanation
Correct Answer: A
The vertex form of a quadratic function is given by the formula x = -b/(2a). Here, a = 2 and b = -8, so x = 8/4 = 2. To find the y-coordinate, substitute x back into the function: f(2) = 2(2)^2 - 8(2) + 6 = 2(4) - 16 + 6 = 8 - 16 + 6 = -2.
Q10
Hard
The function g(x) = 3x - 5 has a linear graph. If a line with slope 2 intersects g(x) at the point (p, g(p)), what is the value of p?
A.
1
B.
2
C.
3
D.
4
Show Answer & Explanation
Correct Answer: B
To find the point of intersection, set the line y = 2x + c equal to g(x) = 3x - 5. Solving yields 2x + c = 3x - 5. Rearranging gives x = 5 + c. By substituting p = 2 into g(x), we find g(2) = 3(2) - 5 = 1. Using the slope of 2, we can deduce that the line must also yield y = 1 when x = 2, confirming the intersection.
Showing 10 of 145 questions. Start a quiz to practice all questions with scoring and timer.
Practice All 145 Questions →More ENEM Matemática Chapters
Other ENEM (Brazil) Subjects
Funções — ENEM (Brazil) ENEM Matemática Practice Questions Online
This page contains 145 practice MCQs for the chapter Funções in ENEM (Brazil) ENEM Matemática. The questions are organized by difficulty — 44 easy, 72 medium, 29 hard — so you can choose the right level for your preparation.
Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit.