1) $$(x+9)^2 = x^2 + 2*9*x + 9^2 = x^2 + 18x + 81$$
2) $$(3a-8b)^2 = (3a)^2 - 2*3a*8b + (8b)^2 = 9a^2 - 48ab + 64b^2$$
3) $$(m-7)(m+7) = m^2 - 7^2 = m^2 - 49$$
4) $$(6a+10b)(10b-6a) = 100b^2 - 36a^2$$
1) $$x^2 + 18x + 81$$
2) $$9a^2 - 48ab + 64b^2$$
3) $$m^2 - 49$$
4) $$100b^2 - 36a^2$$