Решение:
\[ (6-p)^2 = 36 - 12p + p^2 \]
\[ 9(p-5) = 9p - 45 \]
\[ (36 - 12p + p^2) + (9p - 45) \]
\[ p^2 + (-12p + 9p) + (36 - 45) = p^2 - 3p - 9 \]
\[ (-0.4)^2 - 3(-0.4) - 9 = 0.16 + 1.2 - 9 = 1.36 - 9 = -7.64 \]
Ответ: -7.64