b) [tex](\frac{3}{4})^2=\frac{3^2}{4^2}=\frac{9}{16}\\\\(\frac{3}{4})^3=\frac{3^3}{4^3}=\frac{27}{64}\\\\(\frac{3}{4})^4=\frac{3^4}{4^4}=\frac{81}{256}[/tex]
c) [tex](-\frac{2}{5})^2=-\frac{2}{5}\cdot-\frac{2}{5}=\frac{2\cdot2}{5\cdot5}=\frac{4}{25}\\\\(-\frac{2}{5})^3=-\frac{2^3}{5^3}=-\frac{8}{125}\\\\(-\frac{2}{5})^4=-\frac{2}{5}\cdot-\frac{2}{5}\cdot-\frac{2}{5}\cdot-\frac{2}{5}=-\frac{2^4}{5^4}=-\frac{16}{625}[/tex]
[tex](\frac{a}{b})^2=\frac{a^2}{b^2}[/tex]
b) [tex](\frac{3}{4})^2=\frac{3^2}{4^2}=\frac{9}{16}\\\\(\frac{3}{4})^3=\frac{3^3}{4^3}=\frac{27}{64}\\\\(\frac{3}{4})^4=\frac{3^4}{4^4}=\frac{81}{256}[/tex]
c) [tex](-\frac{2}{5})^2=-\frac{2}{5}\cdot-\frac{2}{5}=\frac{2\cdot2}{5\cdot5}=\frac{4}{25}\\\\(-\frac{2}{5})^3=-\frac{2^3}{5^3}=-\frac{8}{125}\\\\(-\frac{2}{5})^4=-\frac{2}{5}\cdot-\frac{2}{5}\cdot-\frac{2}{5}\cdot-\frac{2}{5}=-\frac{2^4}{5^4}=-\frac{16}{625}[/tex]