All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
We have already issued Fatwa 82399 clarifying the pre-conditions for a woman to work, among which is not mixing with men.
Mixing between men and women is a means that leads to temptation and a Muslim should seek safety of her religion.
Therefore, if teaching in these schools includes forbidden mixing with non-Mahram men, then it is not permissible for you to join this job except for a necessity, like if you have no one to spend on you and you did not find another job which is free from prohibitions, in which case you are permitted to join this work for a necessity. When you will no longer be in necessity, you are obliged to leave this job.
For more benefit, please refer to Fataawa 84281 and 90066.
Allaah Knows best.