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Functions and Notation
Example 3

Example 3: Function Evaluation

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

Problem

If f(x)=3x6, find f(2)\text{If }f(x)=-3x-6\text{, find }f(2)

1. Recognize Pattern

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

2. Apply Method

f(x)=2x1,  f(2)=3f(x)=2x-1,\;f(2)=3

3. Conclude

f(2)=3(2)6=12f(2)=-3(2)-6=-12

Final answer

f(2)=3(2)6=12f(2)=-3(2)-6=-12