\[\boxed{\text{1043\ (1043).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[4x^{2} - 12x + a + 6 = 0,\]
\[Одна\ точка\ пересечения,\ \]
\[если\ D = 0:\]
\[D = 144 - 4 \cdot 4 \cdot (a + 6) =\]
\[= 144 - 16a - 96 = 48 - 16a,\]
\[48 - 16a = 0\]
\[a = 3.\]
\[4x^{2} - 12x + 9 = 0\]
\[x = 1,5,\]
\[y = - 3 \cdot (1,5)^{2} + 5 \cdot 1,5 - 6 =\]
\[= - 5,25.\]
\[Ответ:a = 3;\ \ (1,5;\ - 5,25).\]