Please explain verb stem changes when answering question?

Am stuck on a section in my grammer book at present.

Can someone please explain why when the question is '?subimos las maletas?' the answer would be 'suben las maletas ahora' and not 'subimos las maletas ahora'.

Isn't suben the word for 'they' rather than 'we'?

Sorry to confirm the answer is 'si, subanlas'

Don't understand why 'subanlas' and not 'subimoslas'

This is one of a number of questions and answers, none of which I understand for this reason. Why is the answer 'they (suben) and not we (subimos)

Welcome to the forums!

There's an 'Accents' drop-down menu just above where you type so you can insert all the special characters needed when typing in Spanish.

The book's answer may make more sense to you if I provide a translation. I'm guessing at the situation, since I haven't seen your textbook. :)

¿Subimos las maletas? = Should we take the suitcases up? (colloquial question asking for permission)
Sí, súbanlas ahora. = Yes, take them up now.

The question is being asked by the porters/bellhops.
The answer is a direct command to them.

Ah brilliant. Thank you very much. That is exactly it.

I mis-read the questions and because there is no explantion on the page, was getting worried that I had missed something regarding the verb stems and how they are used

thanks :-)

You're welcome. What you're calling verb stems are actually verb endings. The stem, known as the radical, is the part of the verb that conveys the meaning. The ending is what changes for each person.

Stems do change, though. There are many stem-changing verbs in Spanish. Here are just a few. The stem is underscored, the vowel in the stem changes:
querer: e -> ie; quiero
pedir: e -> i; pido
dormir: o - ue; duermo and, in some conjugations, o -> u; durmió