Precalculus Examples

If $f (x) = 2 x$ and $g (x) = 5 x$ ; what is $f (g (x))$ when $x = 3$ ?

Step 1

Set up the composite result function.

$f (f (g (x)))$

Step 2

Evaluate $f (5 x)$ by substituting in the value of $g$ into $f$ .

$f (5 x) = 2 (5 x)$

Step 3

Multiply $5$ by $2$ .

$f (5 x) = 10 x$