Answer
$i = -87.5~cm$
Work Step by Step
We can find $i$:
$\frac{1}{i}+\frac{1}{p} = \frac{1}{f}$
$\frac{1}{i} = \frac{1}{f}-\frac{1}{p}$
$\frac{1}{i} = \frac{1}{35~cm}-\frac{1}{25~cm}$
$\frac{1}{i} = \frac{5}{175~cm}-\frac{7}{175~cm}$
$\frac{1}{i} = -\frac{2}{175~cm}$
$i = -\frac{175~cm}{2}$
$i = -87.5~cm$
