## Precalculus (6th Edition) Blitzer

$6.3\times10^{7}$
$(3\times10^{4})$$(2.1\times10^{3})$ = $3.1\times2.1\times10^{4}\times10^{3}$ = $6.3\times10^{7}$ Group like terms and when multiplying exponents with the same bases, add the exponents and keep the base the same.