\[\boxed{\text{477\ (477).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
Пояснение.
Решение.
\[1)\ ay - 3y - 4a + 12 =\]
\[= (ay - 3y) - (4a - 12) =\]
\[= y \cdot (a - 3) - 4 \cdot (a - 3) =\]
\[= (a - 3) \cdot (y - 4).\]
\[2)\ 9a + 9 - na - n =\]
\[= (9a + 9) - (na + n) =\]
\[= 9 \cdot (a + 1) - n \cdot (a + 1) =\]
\[= (a + 1) \cdot (9 - n).\]
\[3)\ 6x + ay + 6y + ax =\]
\[= (6x + 6y) + (ay + ax) =\]
\[= 6 \cdot (x + y) + a \cdot (y + x) =\]
\[= (x + y) \cdot (6 + a).\]
\[4)\ 8x - 8y + xz - yz =\]
\[= (8x - 8y) + (xz - yz) =\]
\[= 8 \cdot (x - y) + z \cdot (x - y) =\]
\[= (x - y) \cdot (8 + z).\]
\[5)\ mn + m - n - 1 =\]
\[= (mn + m) - (n + 1) =\]
\[= m \cdot (n + 1) - (n + 1) =\]
\[= (n + 1) \cdot (m - 1).\]
\[6)\ ab - ac - 2b + 2c =\]
\[= (ab - 2b) - (ac - 2c) =\]
\[= b \cdot (a - 2) - c \cdot (a - 2) =\]
\[= (a - 2) \cdot (b - c)\text{.\ }\]