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Functions and Notation
Example 8

Example 8: Function Evaluation

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

Problem

If f(x)=5x−3, find f(7)\text{If }f(x)=5x-3\text{, find }f(7)

1. Recognize Pattern

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

2. Apply Method

f(x)=−2x+1,  f(−1)=3f(x)=-2x+1,\;f(-1)=3

3. Conclude

f(7)=5(7)−3=32f(7)=5(7)-3=32

Final answer

f(7)=5(7)−3=32f(7)=5(7)-3=32
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