1) $$(p+8)^2 = p^2 + 2*8*p + 8^2 = p^2 + 16p + 64$$
2) $$(10x-3y)^2 = (10x)^2 - 2*10x*3y + (3y)^2 = 100x^2 - 60xy + 9y^2$$
3) $$(x-9)(x+9) = x^2 - 9^2 = x^2 - 81$$
4) $$(4m+7n)(7n-4m) = (7n+4m)(7n-4m) = (7n)^2 - (4m)^2 = 49n^2 - 16m^2$$
**Ответ:**
1) $$p^2 + 16p + 64$$
2) $$100x^2 - 60xy + 9y^2$$
3) $$x^2 - 81$$
4) $$49n^2 - 16m^2$$