Solved Examples and Worksheet for Finding Values of a Function for a given Domain

Q1Evaluate the function h(x) = 4x + 9 for x = - 1, 0, 1.
A. 5, 13, 13
B. 4, 9, 9
C. 5, 9, 13
D. 5, 9, 15

Solutions
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Step: 1
h(x) = 4x + 9
Step: 2
h(- 1) = 4(- 1) + 9 = 5
  [Substitute the values.]
Step: 3
h(0) = 4(0) + 9 = 9
  [Substitute the values.]
Step: 4
h(1) = 4(1) + 9 = 13
  [Substitute the values.]
Correct Answer is :   5, 9, 13
Q2If f(x) = 5x2 - 7, then find the value of f(- 6).


A. 180
B. 173
C. 36
D. - 7

Solutions
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Step: 1
f(x) = 5x2 - 7
Step: 2
f(- 6) = 5(- 6)2 - 7 = 173
  [Substitute the values.]
Correct Answer is :   173
Q3Evaluate the function h(x) = 2x + 9 for x = - 1, 0, 1, x.

A. 7, 9, 13, 2x + 9
B. 2, 9, 9, 2x + 9
C. 7, 11, 11, 2x + 9
D. 7, 9, 11, 2x + 9

Solutions
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Step: 1
h(x) = 2x + 9
Step: 2
h(- 1) = 2(- 1) + 9 = 7
  [Substitute the values.]
Step: 3
h(0) = 2(0) + 9 = 9
  [Substitute the values.]
Step: 4
h(1) = 2(1) + 9 = 11
  [Substitute the values.]
Step: 5
h(x) = 2(x) + 9 = 2x + 9
  [Substitute the values.]
Correct Answer is :   7, 9, 11, 2x + 9
Q4If g(x) = x2 + 5x + 1, find g(- 5).
A. 51
B. 26
C. 1
D. - 29

Solutions
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Step: 1
g(x) = x2 + 5x + 1
  [Given.]
Step: 2
g(- 5) = (- 5)2 + 5(- 5) + 1
  [Replace x with - 5.]
Step: 3
= 25 - 25 + 1 = 1
  [Multiply and Subtract.]
Correct Answer is :   1
Q5Evaluate the function f(x) = 8x + 9 for x = - 7, 0, 7.

A. 0, 9, 0
B. 65, 9, - 65
C. 65, 9, - 47
D. - 47, 9, 65

Solutions
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Step: 1
f(x) = 8x + 9
Step: 2
f(- 7) = - 56 + 9 = - 47
  [Substitute x = - 7.]
Step: 3
f(0) = 0 + 9 = 9
  [Substitute x = 0.]
Step: 4
f(7) = 56 + 9 = 65
  [Substitute x = 7.]
Correct Answer is :   - 47, 9, 65
Q6Which of the following tables represents the function f(x) = 23x - 1, for x = 0, 3, 6, 9 and 12 as domain?

A. Table 3
B. Table 2
C. Table 1
D. Table 4

Solutions
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Step: 1
f(x) = 23 x - 1
  [Given function.]
Step: 2
For x = 0, f(0) = 23 (0) - 1 = 0 - 1 = - 1
  [Substitute the domain values in the function.]
Step: 3
For x = 3, f(3) = 23 (3) - 1 = 2 - 1 = 1
Step: 4
For x = 6, f(6) = 23 (6) - 1 = 4 - 1 = 3
Step: 5
For x = 9, f(9) = 23 (9) - 1 = 6 - 1 = 5
Step: 6
For x = 12, f(12) = 23 (12) - 1 = 8 - 1 = 7
Step: 7
The values of x and f(x) can be tabulated as shown in table 1.
Step: 8
Therefore, Table 1 describes the given function.
Correct Answer is :   Table 1
Q7Which of the function tables represents the function f(x) = 9x - 11, for x = -1, 1, 2, 3 and 5 as domain ?


A. Table 1
B. Table 3
C. Table 4
D. Table 2

Solutions
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Step: 1
f(x) = 9x - 11
  [Given function.]
Step: 2
For x = -1, f( - 1) = 9 (- 1) - 11 = - 9 - 11 = - 20
  [Substitute the domain values in the function.]
Step: 3
For x = 1, f (1) = 9(1) - 11 = 9 - 11 = - 2
Step: 4
For x = 2, f (2) = 9(2) - 11 = 18 - 11 = 7
Step: 5
For x = 3, f (3) = 9(3) - 11 = 27 - 11 = 16
Step: 6
For x = 5, f (5) = 9(5) - 11 = 45 - 11 = 34
Step: 7
The values of x and f(x) can be tabulated as shown in Table 2.
Step: 8
Therefore, Table 2 describes the given function.
Correct Answer is :   Table 2
Q8Which of the function tables represents the function f(x) = 3x - 10, for x = 0, 5, 10, 15 and 20 as domain ?


A. Table 2
B. Table 1
C. Table 4
D. Table 3

Solutions
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Step: 1
f(x) = 3x - 10
  [Given function]
Step: 2
For x = 0, f(x) = 3(0) - 10 = 0 - 10 = - 10
  [Substitute the domain values in the function.]
Step: 3
For x = 5, f(5) = 3(5) - 10 = 15 - 10 = 5
Step: 4
For x = 10, f(10) = 3(10) - 10 = 30 - 10 = 20
Step: 5
For x = 15, f(15) = 3(15) - 10 = 45 - 10 = 35
Step: 6
For x = 20, f(20) = 3(20) - 10 = 60 - 10 = 50
Step: 7
The values of x and f(x) can be tabulated as shown in table 4.
Step: 8
therefore, Table 4 describes the given function.
Correct Answer is :   Table 4
Q9Which of the function tables represents the function f(x) = 5 - 11x, for x = - 2, 0, 2, 4 and 6 as domain?



A. Table 3
B. Table 1
C. Table 2
D. Table 4

Solutions
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Step: 1
f(x) = 5 - 11x
  [Given function]
Step: 2
For x = - 2, f( - 2) = 5 - 11( - 2) = 5 + 22 = 27
  [Substitute the domain values in the function.]
Step: 3
For x = 0, f(0) = 5 - 11(0) = 5 - 0 = 5
Step: 4
For x = 2, f(2) = 5 - 11(2) = 5 - 22 = - 17
Step: 5
For x = 4, f(4) = 5 - 11(4) = 5 - 44 = - 39
Step: 6
For x = 6, f(6) = 5 - 11(6) = 5 - 66 = - 61
Step: 7
The values of x and f(x) can be tabulated as shown in Table 1.
Step: 8
Therefore, Table 1 describes the given function.
Correct Answer is :   Table 1

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