536.
a)
(a^2 - 1/b^2) : (a - 1/b) = (a^2b^2 - 1)/b^2 * b/(ab - 1) = ((ab - 1)(ab + 1))/b^2 * b/(ab - 1) = (ab + 1)/b
б)
((3a^2)/(4ab^2) - b^2/3) : ((3a)/(2b) + b) = (9a^2 - 4ab^4)/(12ab^2) * (2b)/(3a + 2b^2) = ((3a - 2ab^2)*(3a + 2ab^2))/(12ab^2) * (2b)/(3a + 2b^2) = (3a - 2ab^2)/(6ab) = (a(3 - 2b^2))/(6ab) = (3-2b^2)/(6b)
в)
(4x^2 - 1/(9b^2) : (2x - 1/(3b)) = (36x^2b^2 - 1)/(9b^2) * (3b)/(6xb - 1) = ((6xb - 1)(6xb + 1))/(9b^2) * (3b)/(6xb - 1) = (6xb + 1)/3b