Разложите на множители:
1) $(a^2 + b^2)^2 - 4a^2b^2$;
2) $81 - (x^2 + 6x)^2$;
3) $a^2 + 2ab + b^2 - c^2$;
4) $c^2 + 4c + 4 - k^2$;
5) $9a^2 + c^2 + 6ac - 9$;
6) $a^2 - b^2 - 10b - 25$;
7) $49 - y^2 + x^2 - 14x$;
8) $mn^2 - m^3 - 12m^2 - 36m$.
$(a^2 + b^2)^2 - 4a^2b^2 = (a^2 + b^2)^2 - (2ab)^2 = (a^2 + b^2 - 2ab)(a^2 + b^2 + 2ab)$
$81 - (x^2 + 6x)^2 = 9^2 - (x^2 + 6x)^2 = (9 - x^2 - 6x)(9 + x^2 + 6x)$
$a^2 + 2ab + b^2 - c^2 = (a^2 + 2ab + b^2) - c^2 = (a + b)^2 - c^2 = (a + b - c)(a + b + c)$
$c^2 + 4c + 4 - k^2 = (c^2 + 4c + 4) - k^2 = (c + 2)^2 - k^2 = (c + 2 - k)(c + 2 + k)$
$9a^2 + c^2 + 6ac - 9 = (9a^2 + 6ac + c^2) - 9 = (3a + c)^2 - 3^2 = (3a + c - 3)(3a + c + 3)$
$a^2 - b^2 - 10b - 25 = a^2 - (b^2 + 10b + 25) = a^2 - (b + 5)^2 = (a - b - 5)(a + b + 5)$
$49 - y^2 + x^2 - 14x = (x^2 - 14x + 49) - y^2 = (x - 7)^2 - y^2 = (x - 7 - y)(x - 7 + y)$
$mn^2 - m^3 - 12m^2 - 36m = m(n^2 - m^2 - 12m - 36) = m(n^2 - (m^2 + 12m + 36)) = m(n^2 - (m + 6)^2) = m(n - m - 6)(n + m + 6)$
Пожауйста, оцените решение