Expand the Logarithmic Expression log of y/1000

$\log (\frac{y}{1000})$

Rewrite $\log (\frac{y}{1000})$ as $\log (y) - \log (1000)$ .

$\log (y) - \log (1000)$

Logarithm base $10$ of $1000$ is $3$ .

$\log (y) - 1 \cdot 3$

Multiply $- 1$ by $3$ .

$\log (y) - 3$