\[\boxed{\mathbf{766\ (766).\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[1)\ a² - 14ab + 40b^{2} =\]
\[= a^{2} - 10ab - 4ab + 40b^{2} =\]
\[= a(a - 10b) - 4b(a - 10b) =\]
\[= (a - 4b)(a - 10b)\]
\[2)\ 12b² + bc - 6c^{2} =\]
\[= 12b^{2} + 9bc - 8bc - 6c^{2} =\]
\[= 3b(4b + 3c) - 2c(4b + 3c) =\]
\[= (4b + 3c)(3b - 2c)\]