\[\boxed{\mathbf{909\ (909)}\mathbf{.}\mathbf{\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[\textbf{а)}\ 1,5 \bullet (1 + x) = 4,5\]
\[1 + x = 4,5\ :1,5\]
\[1 + x = 45\ :15\]
\[1 + x = 3\]
\[x = 3 - 1\]
\[x = 2.\]
\[Ответ:x = 2.\]
\[\textbf{б)}\ 2 \bullet (x - 7) = 1\]
\[x - 7 = 1\ :2\]
\[x - 7 = 0,5\]
\[x = 7 + 0,5\]
\[x = 7,5.\]
\[Ответ:x = 7,5.\]