How do you find the domain of f(x) = 5 + ln(7x + 6)?

We must have $7 x + 6 > 0$ or $7 x > - 6$ or $x > - \frac{6}{7}$
Hence the domain of $f$ is ${D}_{f} = \left(- \frac{6}{7} , + \infty\right)$