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Functions and Notation
Example 4

Example 4: Function Evaluation

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

Problem

If f(x)=−3x−3, find f(−1)\text{If }f(x)=-3x-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)=4x+3,  f(−5)=−17f(x)=4x+3,\;f(-5)=-17

3. Conclude

f(−1)=−3(−1)−3=0f(-1)=-3(-1)-3=0

Final answer

f(−1)=−3(−1)−3=0f(-1)=-3(-1)-3=0
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