# Algebra 1 : How to find f(x)

## Example Questions

### Example Question #81 : How To Find F(X)

If

and

,

then what is the value of ?

Explanation:

This type of problem is very common on standardized tests, and examines a student's confidence level when dealing with unfamiliar material. Clearly, we don't learn how to "diamond" numbers in class! The diamond symbol, however, just represents some unknown operation. Here, to diamond two numbers simply means raising the first number to the negative second number. The solution is provided below:

First evaluate f(5). This simplifies to:

.

Now, we know that the question is asking for the value of:

.

The rest of the solution is a simple matter of dealing with a negative exponent. Based on the laws of exponents, we know that

.

Therefore, the answer to this question is 0.01.

### Example Question #82 : How To Find F(X)

If

find  .

Explanation:

Given

we must find .

All we do is substitute -4 for the variable x.

So anywhere we see x, we will change to -4.

We get

### Example Question #83 : How To Find F(X)

Find  if

.

Explanation:

Given , when solving

we simply substitute.

In this case .  So anywhere we see an x, we will substitute -2.  So,

### Example Question #84 : How To Find F(X)

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

### Example Question #85 : How To Find F(X)

If , solve

Explanation:

To solve a function, we simply substitute the value of x into the equation.  So, given that

we will substitute into the function.

### Example Question #86 : How To Find F(X)

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.

### Example Question #87 : How To Find F(X)

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.

### Example Question #88 : How To Find F(X)

Given the following zeros, write out the polynomial function, but don't expand:

Explanation:

To find the polynomial function given the zeros of the function, we must work backwards. If we know that each zero came from a term that was set equal to x, and this term was either added or subtracted to x, we can simply flip the sign on all of the zeros to get the polynomial function they came from:

### Example Question #89 : How To Find F(X)

If , solve the following function:

Explanation:

When solving a function, we substitute the value of x into the function itself.  So, we know that .  We will substitute this value into the given function.

### Example Question #90 : How To Find F(X)

If , solve the following function: