## Precalculus (6th Edition) Blitzer

$390,000$
$(3\times10^3)(1.3\times10^2)=3\times1.3\times10^3\times10^2=3.9\times10^5$ Since we're multiplying $3.9$ by $10^5$, we move the decimal place five digits to the right, giving us $390,000$.