Question

what is the voice of the following sentence? we were left by the teacher to figure out how to do the math homework. passive active

Answer 1

The voice of the given sentence above is in the passive voice. When a sentence is written in the passive voice, the subject in the sentence becomes the receiver of the action of the verb. The subject of the given sentence above is "we" which receives the action of the verb "were left". 

Answer 2

What is the voice of the following sentence?

we were left by the teacher to figure out how to do the math homework.
The voice used on the sentence presented above is passive voice. The way it is form is by combining a form of the “to be verb” with the past participle of the main verb.

Answer: Passive Voice

I hope it helps, Regards.