Function Notation f(x)

Show your work for each problem.

1.
What does mean?
1. a)f plus x
2. b)f of x (the output when x is the input)
3. c)f multiplied by x
4. d)f divided by x
Answer: f of x (the output when x is the input)
is read as 'f of x' and means the output of function when the input is . The parentheses indicate a function, not multiplication.
2.
If , what is ?
Answer: 8
. We substitute for in the function rule.
3.
If , what is ?
Answer: 14
. Multiply the input by 2.
4.
If , what is ?
1. a)
2. b)
3. c)
4. d)
Answer:
. The function subtracts 4 from the input.
5.
If , find .
Answer: 13
1. What value are you substituting for x? 4
2. What is ? 12
3. What is ? 13
6.
If , what is ?
Answer: 7
7.
If , what is ?
Answer: 24
8.
If , what is ?
1. a)
2. b)
3. c)
4. d)
Answer:
. Remember: , not .
9.
If , find .
Answer: -11
1. What is the input value? -2
2. What is ? -8
3. What is ? -11
10.
If , find .
Answer: 10
1. What is ? 4
2. What is ? 6
3. What is ? 10
11.
If and , which is greater: or ?
1. a)Cannot be determined
2. b)They are equal
3. c) is greater
4. d) is greater
Answer: is greater
and . Since , is greater.
12.
If and , what is ?
Answer: 5
If , then . Solving: , so . Check: .
13.
If , find .
Answer: 9
1. First, find . What is ? 5
2. Now find . What is ? 9
14.
If and , find the positive value of .
Answer: 4
1. Set up the equation. What is equal to? 12
2. Add 4 to both sides. What is ? 16
3. Take the square root. What is the positive value of ? 4
15.
If and , what is ?
1. a)
2. b)
3. c)
4. d)
Answer:
First: . Then: . So .
16.
The cost of a taxi ride is given by where is the number of kilometers. If a ride costs 17 euros, how many kilometers was the ride?
Answer: 7
1. Set up the equation. what? 17
2. Subtract 3 from both sides. What is ? 14
3. Divide by 2. What is ? 7