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Question
If f(x) = x + 7 and g(x) = x − 7, x ∈ R, write fog (7).
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Solution
\[\left( fog \right)\left( 7 \right) = f \left( g\left( 7 \right) \right)\]
\[ = f\left( 7 - 7 \right)\]
\[ = f \left( 0 \right)\]
\[ = 0 + 7\]
\[ = 7\]
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