\[\boxed{\text{657\ (657).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
Пояснение.
Решение.
\[\textbf{а)}\ 7ax + 7bx = 7x(a + b)\]
\[\textbf{б)}\ 3by - 6b = 3b(y - 2)\]
\[\textbf{в)} - 5mn + 5n = 5n(1 - m)\]
\[\textbf{г)}\ 3a + 9ab = 3a(1 + 3b)\]
\[\textbf{д)}\ 5y^{2} - 15y = 5y(y - 3)\ \]
\[\textbf{е)}\ 3x + 6x^{2} = 3x(1 + 2x)\]
\[\textbf{ж)}\ a^{2} - ab = a(a - b)\]
\[\textbf{з)}\ 8mn - 4m^{2} = 4m(2n - m)\]
\[\textbf{и)} - 6ab + 9b^{2} = 3b(3b - 2a)\]
\[к)\ x^{2}y - xy^{2} = xy(x - y)\]
\[л)\ ab - a^{2}b = ab(1 - a)\]
\[м) - p^{2}q^{2} - pq = - pq \cdot (pq + 1)\]