\[MC = 27\ дм,\ \ BC = 8\ дм,\]
\[\ \ CN = 5\ дм.\]
\[MB - ?\ \ \ \ BN - ?\]
\[MB = MC - BC = 27 - 8 =\]
\[= 19\ дм.\]
\[BN = BC + CN = 8 + 5 =\]
\[= 13\ дм.\]
\[Ответ:19\ дм;\ \ 13\ дм.\]