a)
\[(x + 8)^2 = x^2 + 2*8*x + 8^2 = x^2 + 16x + 64\]
б)
\[(7-x)(7+x) = 7^2 - x^2 = 49 - x^2\]
в)
\[(5y - c)^2 = (5y)^2 - 2*5y*c + c^2 = 25y^2 - 10yc + c^2\]
г)
\[(6a - 3)(6a + 3) = (6a)^2 - 3^2 = 36a^2 - 9\]
д)
\[(x^2 + 10)(x^2 - 10) = (x^2)^2 - 10^2 = x^4 - 100\]
**Ответ:**
a) \[x^2 + 16x + 64\]
б) \[49 - x^2\]
в) \[25y^2 - 10yc + c^2\]
г) \[36a^2 - 9\]
д) \[x^4 - 100\]