Номер 50 гдз 8 класс алгебра Муравин Муравина


Номер 50

 

\begin{equation} 1)\frac{2x^{3}-y^{3}}{x^{3}+x^{2}y-3xy^{2}} \end{equation} \begin{equation} \frac{2\cdot (kx)^{3}-(ky)^{3}}{(kx)^{3}+(kx)^{2}\cdot (ky)-}= \end{equation} \begin{equation} \frac{}{-3\cdot (kx)\cdot (ky)^{2}}= \end{equation} \begin{equation} =\frac{2\cdot k^{3}x^{3}-k^{3}y^{3}}{k^{3}x{3}+k^{2}x^{2}\cdot }= \end{equation} \begin{equation} =\frac{}{\cdot ky-3kx\cdot k^{2}y^{2}}= \end{equation} \begin{equation} =\frac{k^{3}(2x^{3}-y^{3})}{k^{3}x{3}+k^{3}x^{2}y-3k^{3}xy^{2}}= \end{equation} \begin{equation} =\frac{k^{3}(2x^{3}-y^{3})}{k^{3}(x^{3}+x^{2}y-3xy^{2})}= \end{equation} \begin{equation} =\frac{2x^{3}-y^{3}}{x^{3}+x^{2}y-3xy^{2}}; \end{equation} \begin{equation} 2)x=\frac{3}{11},y=\frac{2}{11} \end{equation} \begin{equation} \frac{2\cdot (\frac{3}{11})^{3}-(\frac{2}{11})^{3}}{(\frac{3}{11})^{3}+(\frac{3}{11})^{2}\cdot \frac{2}{11}-} \end{equation} \begin{equation} \frac{}{-3\cdot \frac{3}{11}\cdot (\frac{3}{11})^{2}}= \end{equation} \begin{equation} =\frac{2\cdot \frac{1}{11^{3}}-(3^{3}-2^{3})}{(\frac{3}{11})^{3}+(\frac{3^{2}\cdot 2}{11^{2}}-\frac{3^{2}\cdot 2^{2}}{11^{2}}}= \end{equation} \begin{equation} =\frac{2\cdot \frac{1}{11^{3}}-(9-8)}{(\frac{1}{11})^{3}\cdot (3^{3}+9\cdot 2-9\cdot 4)}= \end{equation} \begin{equation} =\frac{2}{27+18-36}=\frac{2}{9}. \end{equation}