The password on the All-in-One Homeschool course answer pages is

parentsonly

lowercase, all one word, just like that.

This is not the password that you created for your online account. And you cannot change this answers password to something else.

Check the answers in an incognito window or on a different computer or browser if you don’t want your child to have access to the answers. The browser will remember the password once you type it in.