Question:
Let $f(x)=x+7$ and $g(x)=x-7, x \in$ R. Find $(f \circ g)(7)$
Solution:
To find: (f o g) (7)
Formula used: $f \circ g=f(g(x))$
Given: (i) $f(x)=x+7$
(ii) $g(x)=x-7$
We have,
$f \circ g=f(g(x))=f(x-7)=[(x-7)+7]$
$\Rightarrow X$
(f o g) $(x)=x$
$(f \circ g)(7)=7$
Ans). (f o g) (7) =7