a) $$2(3x - 2y)(3x + 2y) = 2((3x)^2 - (2y)^2) = 2(9x^2 - 4y^2) = 18x^2 - 8y^2$$
б) $$(a^3 + b^2)^2 = (a^3)^2 + 2*a^3*b^2 + (b^2)^2 = a^6 + 2a^3b^2 + b^4$$
в) $$(a - 5)^2 - (a + 5)^2 = (a^2 - 10a + 25) - (a^2 + 10a + 25) = a^2 - 10a + 25 - a^2 - 10a - 25 = -20a$$
Ответы:
a) $$18x^2 - 8y^2$$
б) $$a^6 + 2a^3b^2 + b^4$$
в) $$-20a$$