Answer
$-30cm$
Work Step by Step
First we consider combining equations 34-9 and 34-10:
$\frac{1}{p}+\frac{1}{i}=(n-1)(\frac{1}{r_1} - \frac{1}{r_2})$
Solving for the image distance, $i$, we obtain :
$i=((n-1)(\frac{1}{r_1} - \frac{1}{r_2})-\frac{1}{p})^{-1}$
Putting in the given values from the table, we have:
$i=((1.70-1)(\frac{1}{42cm} - \frac{1}{33cm})-\frac{1}{35cm})^{-1}$
$i=-30cm$
