# Two converging lens, find the final image...

1. Jul 31, 2016

1. The problem statement, all variables and given/known data

2. Relevant equations

$$\frac{1}{p}+\frac{1}{q}=\frac{1}{f}$$
3. 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.

2. Jul 31, 2016

### Simon Bridge

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