\[ (k+8)^2 - 7(k+9) = (k^2 + 16k + 64) - (7k + 63) \]
\[ k^2 + 16k + 64 - 7k - 63 = k^2 + 9k + 1 \]
\[ (0.8)^2 + 9(0.8) + 1 = 0.64 + 7.2 + 1 = 8.84 \]
Ответ: 8,84