0\to x > 0\\\\3log3x=8\ \ \ \ /:3\\\\log3x=\frac{8}{3}\\\\log3x=log10^\frac{8}{3}\iff3x=10^\frac{8}{3}\ \ \ \ /:3\\\\x=\frac{10^{2\frac{2}{3}}}{3}\\\\x=\frac{100\sqrt[3]{100}}{3}" alt="log3x+2log3x=8;\ D:3x > 0\to x > 0\\\\3log3x=8\ \ \ \ /:3\\\\log3x=\frac{8}{3}\\\\log3x=log10^\frac{8}{3}\iff3x=10^\frac{8}{3}\ \ \ \ /:3\\\\x=\frac{10^{2\frac{2}{3}}}{3}\\\\x=\frac{100\sqrt[3]{100}}{3}" align="absmiddle" class="latex-formula">