What is the inverse of f(x)=ln(x-6)

To find the inverse of a function, simply switch the x and f(x).  Then make it so that the equation is set equal to f(x).  Also note that ln is the log of e:

f(x) = ln(x - 6)

x = ln(f(x) - 6)

e^x = f(x) - 6

She should use 12/3 to measure