Skip to content
Functions and Notation
Example 11

Example 11: Function Evaluation

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

Problem

If f(x)=4x+3, find f(−1)\text{If }f(x)=4x+3\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)=−3x−2,  f(7)=−23f(x)=-3x-2,\;f(7)=-23

3. Conclude

f(−1)=4(−1)+3=−1f(-1)=4(-1)+3=-1

Final answer

f(−1)=4(−1)+3=−1f(-1)=4(-1)+3=-1
Previous exampleNext exampleBack to lessonsPractice this skillTry in calculator