How to find f(x)

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Algebra › How to find f(x)

Questions 1 - 10
1

Explanation

2

If , then solve

Explanation

We know . When solving a function, we substitute the value of x into the function. In other words, anywhere we see an x, we will replace it with -4.

3

If , solve for if .

Explanation

We are given an equation that is a function of x. Substitute the given fraction and replace it with the variable.

Simplify the right side.

The answer is:

4

.

Find .

Explanation

Finding means plugging in in place of x into the function . In this case, we are told that , so we are multiplying by 2 and then adding 17:

order of opperations tells us to first multiply:

and now add:

5

Given a function , what is ?

Explanation

Given a function , we can plug in to get

.

6

If , then solve

Explanation

We know . When solving a function, we substitute the value of x into the function. In other words, anywhere we see an x, we will replace it with 3.

7

Each of the following 4 sets defines a relationship between and . Which of these four sets defines a one-to-one function:

A =

B=

C =

D =

Set A

Set B

Set C

Set D

Set A and Set B

Explanation

Only in set A one can see that there is an unique value of for each value of and similarly each of the values maps into one and only one value. Hence set A must define a one-to-one function.

8

A function is given by . Find .

Explanation

Plugging in 2 wherever is present in the formula yields an answer of 14.

9

If , solve

Explanation

When solving a function, we simply substitute the value into the equation. So, we know . So in the function

we substitute -4 in for x. By doing that, we get

We now solve using the order of operations. We get

10

Given a function , what is ?

Explanation

Given a function

,

we can plug in to get

.

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