[tex] \displaystyle\\
\left(\frac{2}{3}\right)^1+\left(\frac{2}{3}\right)^2+\left(\frac{2}{3}\right)^3+...+ \left(\frac{2}{3}\right)^{100}:(0,6)^{5048}=\\
=\left(\frac{2}{3}\right)^{1+2+2+...+100}:\left(\frac{6}{9}\right)^{5048}=\\
=\left(\frac{2}{3}\right)^{\frac{\bf100\times101}{\bf 2}}:\left(\frac{2}{3}\right)^{5048}=\\
=\left(\frac{2}{3}\right)^{50\times101}:\left(\frac{2}{3}\right)^{5048}=\\
=\left(\frac{2}{3}\right)^{5050}:\left(\frac{2}{3}\right)^{5048}=\\
\left(\frac{2}{3}\right)^{5050-5048}=\frac{4}{9} [/tex]