\[\boxed{\mathbf{794}\mathbf{.}}\]
\[1)\log_{\sqrt{3}}50\]
\[\log_{3}15 = a\ \ и\ \log_{3}10 = b:\]
\[\log_{\sqrt{3}}50 = \log_{3^{\frac{1}{2}}}50 =\]
\[= 1\ :\frac{1}{2} \bullet \log_{3}50 =\]
\[= 2\log_{3}(5 \bullet 10) =\]
\[= 2\left( \log_{3}5 + \log_{3}10 \right) =\]
\[= 2\left( 1 + \log_{3}5 + \log_{3}10 - 1 \right) =\]
\[= 2\left( \log_{3}3 + \log_{3}5 + \log_{3}10 - 1 \right) =\]
\[= 2\left( \log_{3}(3 \bullet 5) + \log_{3}10 - 1 \right) =\]
\[= 2\left( \log_{3}15 + \log_{3}10 - 1 \right) =\]
\[= 2(a + b - 1)\]
\[Ответ:\ \ 2(a + b - 1).\]
\[2)\log_{4}1250\]
\[\log_{2}5 = a:\]
\[\log_{4}1250 = \log_{2^{2}}1250 =\]
\[= \frac{1}{2}\log_{2}(625 \bullet 2) =\]
\[= \frac{1}{2}\left( \log_{2}625 + \log_{2}2 \right) =\]
\[= \frac{1}{2}\left( \log_{2}5^{4} + 1 \right) =\]
\[= \frac{1}{2}\left( 4\log_{2}5 + 1 \right) =\]
\[= \frac{1}{2}(4a + 1) = 2a + \frac{1}{2}\]
\[Ответ:\ \ 2a + \frac{1}{2}\text{.\ }\]