Find f(g(x)) f(x)=7x , g(x)=3x+1

$f (x) = 7 x$ , $g (x) = 3 x + 1$

Step 1

Set up the composite result function.

$f (g (x))$

Step 2

Evaluate $f (3 x + 1)$ by substituting in the value of $g$ into $f$ .

$f (3 x + 1) = 7 (3 x + 1)$

Step 3

Apply the distributive property.

$f (3 x + 1) = 7 (3 x) + 7 \cdot 1$

Step 4

Multiply.

Multiply $3$ by $7$ .

$f (3 x + 1) = 21 x + 7 \cdot 1$

Multiply $7$ by $1$ .

$f (3 x + 1) = 21 x + 7$