Question

how do you solve this?

Answer 1

$\bf ~~~~~~~~~~~~\textit{negative exponents}\\\\ a^{-n} \implies \cfrac{1}{a^n} \qquad \qquad \cfrac{1}{a^n}\implies a^{-n} \qquad \qquad a^n\implies \cfrac{1}{a^{-n}} \\\\ -------------------------------$

$\bf \cfrac{\stackrel{\textit{bacteria's volume}}{1.3\times 10^{15}}}{\stackrel{\textit{planet's surface area}}{5.2\times 10^{14}}}\implies \cfrac{1.3\times 10^{15}\times 10^{-14}}{5.2}\implies \cfrac{1.3\times 10^{15-14}}{5.2} \\\\\\ \cfrac{1.3\times 10}{5.2}\implies \cfrac{13}{5.2}\implies \cfrac{\frac{13}{1}}{\frac{52}{10}}\implies \cfrac{13}{1}\cdot \cfrac{10}{52}\implies \cfrac{130}{52} \\\\\\ \cfrac{5}{2}\implies 2\frac{1}{2}$