\[\boxed{\text{1188\ (1188).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[4a^{2} - 6ab + 9b^{2} - 6ab =\]
\[= 4a^{2} - 12ab + 9b^{2} =\]
\[= (2a - 3b)^{2}\]
\[4a^{2} - 6ab + 9b^{2} + 18ab =\]
\[= (2a + 3b)^{2}\]
\[4a^{2} - 6ab + 9b^{2} - 3a^{2} =\]
\[= (a - 3b)^{2}\ \]