Without using a calculator, solve these two problems from a college entrance exam. 

1. If $x^{−4/3} + 1 = 17$, find $x^{−1/3}$.

   Hint (a):

   Solve the first equation for $x$, then use that value to find the answer.

2. If $\log(A)=a$, find $\log\left(\frac{A}{100}\right)$.

   Answer (b):

   $a - 2$