11) Answer: [tex]-\frac{x^{14}}{y^{13}}[/tex]
[tex]\frac{2xy^{-4}}{\left(x^{-4}y^4\right)^3\left(-2\right)x^{-1}y^{-3}}[/tex]
[tex]=\frac{2xy^{-4}}{-\left(x^{-4}y^4\right)^3\cdot \:2x^{-1}y^{-3}}[/tex]
[tex]=\frac{xy^{-4}}{-\left(x^{-4}y^4\right)^3x^{-1}y^{-3}}[/tex]
[tex]=\frac{x^2y^{-4}}{-\left(x^{-4}y^4\right)^3y^{-3}}[/tex]
[tex]=\frac{x^2}{-\left(x^{-4}y^4\right)^3y}[/tex]
[tex]=-\frac{x^{14}}{y^{13}}[/tex]
12) Answer: [tex]-\frac{1}{u^5v^5}[/tex]
[tex]\left(\frac{2u^4v^0}{-u^{-2}v^{-1}\cdot \:2uv^{-4}}\right)^{-1}[/tex]
[tex]=\frac{1}{\frac{2u^4v^0}{-u^{-2}v^{-1}\cdot \:2uv^{-4}}}[/tex]
[tex]=-\frac{1}{u^5v^5}[/tex]
