\[\boxed{\text{73\ (73).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[Закон:\]
\[l = 60 \cdot (1 + 0,000012t).\]
\[\textbf{а)}\ l(0) =\]
\[= 60 \cdot (1 + 0,000012 \cdot 0) =\]
\[= 60 \cdot 1 = 60\ м.\]
\[l(25) =\]
\[= 60 \cdot (1 + 0,000012 \cdot 25) =\]
\[= 60 \cdot 1,0003 = 60,018\ м.\]
\[l(25) - l(0) = 60,018 - 60 =\]
\[= 0,018\ м = 18\ мм.\]
\[\textbf{б)}\ l(25) = 60,018\ м.\]
\[l(50) =\]
\[= 60 \cdot (1 + 0,000012 \cdot 50) =\]
\[= 60 \cdot 1,0006 = 60,036\ м.\]
\[l(50) - l(25) = 60,036 -\]
\[- 60,018 = 0,018\ м = 18\ мм.\]
\[\boxed{\text{73.\ }\text{ОК\ ГДЗ\ -\ домашка\ на\ 5}}\]