Question

Please help. I need an explanation too so I could do this in class.

Answer 1

`\bf ~\hspace{7em}\textit{negative exponents} \\\\ a^(-n) \implies \cfrac{1}{a^n} ~\hspace{4.5em} a^n\implies \cfrac{1}{a^(-n)} ~\hspace{4.5em} \cfrac{a^n}{a^m}\implies a^na^(-m)\implies a^(n-m) \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ \boxed{13}\qquad m^(-9)\cdot m^5\implies m^(-9+5)\implies m^(-4)\implies \cfrac{1}{m^4}`

`\bf \boxed{15}\qquad 9n^(-3)\implies 9\cdot \cfrac{1}{n^3}\implies \cfrac{9}{n^3} \\\\\\ \boxed{17}\qquad b^3\cdot b^(-4)\cdot b^(-5)\implies b^(3-4-5)\implies b^(-6)\implies \cfrac{1}{b^6} \\\\\\ \boxed{18}\qquad \cfrac{4z^(-2)}{z^4}\implies \cfrac{4}{z^4z^2}\implies \cfrac{4}{z^(4+2)}\implies \cfrac{4}{z^6} \\\\\\ \boxed{20}\qquad \cfrac{18r^(-6)}{3r^3}\implies \cfrac{18}{3}\cdot \cfrac{r^(-6)}{r^3}\implies 6\cdot \cfrac{1}{r^3r^6}\implies \cfrac{6}{r^(3+6)}\implies \cfrac{6}{r^9}`