в) (4a^2 - 1)/(a^2 - 9) * (6a + 3)/(a + 3)

((4a^2 - 1)/(a^2 - 9)) * ((6a + 3)/(a + 3)) = ((2a - 1)(2a + 1)/((a - 3)(a + 3))) * ((6(a + 3))/(a + 3)) = (6(2a - 1)(2a + 1))/(a - 3)