\[\boxed{\text{958.}\text{\ }еуроки - ответы\ на\ пятёрку}\]
\[\textbf{а)}\ 4xy + 12y - 4x - 12 =\]
\[= 4y(x + 3) - 4 \cdot (x + 3) =\]
\[= (x + 3)(4y - 4) =\]
\[= 4 \cdot (x + 3)(y - 1)\]
\[\textbf{б)}\ 60 + 6ab - 30b - 12a =\]
\[= 30 \cdot (2 - b) - 6a \cdot (2 - b) =\]
\[= (2 - b)(30 - 6a) =\]
\[= 6 \cdot (2 - b)(5 - a)\]
\[\textbf{в)} - abc - 5ac - 4ab - 20a =\]
\[= - ac(b + 5) - 4a(b + 5) =\]
\[= - a \cdot (b + 5)(c + 4)\]
\[\textbf{г)}\ a³ + a²b + a² + ab =\]
\[= a^{2}(a + 1) + ab(a + 1) =\]
\[= (a + 1)\left( a^{2} + ab \right) =\]
\[= a \cdot (a + 1)(a + b)\]