Let \( I(x) = \int \dfrac{3\,dx}{(4x+6)(\sqrt{4x^2 + 8x + 3})} \) and \( I(0) = \dfrac{\sqrt{3}}{4} + 20 \). If \( I\!\left(\frac{1}{2}\right) = \dfrac{a\sqrt{2}}{b} + c \), where \( a,b,c \in \mathbb{N} \), \( \gcd(a,b) = 1 \), then \( a + b + c \) is equal to: