Skip to content
Functions and Notation
Example 5

Example 5: Function Evaluation

Step-by-step worked example for this lesson track.

Problem

If f(x)=5x+1, find f(−1)\text{If }f(x)=5x+1\text{, find }f(-1)

1. Recognize Pattern

f(x)=ax+b⇒f(k)=ak+bf(x)=ax+b\Rightarrow f(k)=ak+b

2. Apply Method

f(x)=1x−1,  f(−1)=−2f(x)=1x-1,\;f(-1)=-2

3. Conclude

f(−1)=5(−1)+1=−4f(-1)=5(-1)+1=-4

Final answer

f(−1)=5(−1)+1=−4f(-1)=5(-1)+1=-4
Previous exampleNext exampleBack to lessonsPractice this skillTry in calculator