Why is image distance negative in two-lens system?

[AdkinsJr]

Homework Statement

Homework Equations

$$\frac{1}{p}+\frac{1}{q}=\frac{1}{f}$$

The Attempt at a Solution

I already had this typed in word so here is a screen shot:

I don't understand why the negative is omitted in the "correct answer" "B." In solving this problem I wanted to proceed in finding the image location relative to the first lens, which should be 9.2 cm.

 

[Simon Bridge]

The diagram does not define the axes so the sign is arbitrary.