Решение:
\[ (-4)^2 - (6+y)(y-6) = 16 - (y^2 - 36) \]
\[ 16 - y^2 + 36 = 52 - y^2 \]
y = -7/3
\[ 52 - \left(-\frac{7}{3}\right)^2 = 52 - \frac{49}{9} \]
\[ \frac{52 \times 9}{9} - \frac{49}{9} = \frac{468 - 49}{9} = \frac{419}{9} \]
Ответ: 419/9