Could you read the posting guidelines? If you have a bunch of those problems, maybe you should provide some context, explain what the difficulty is, etc.
Let me know if you figure this one out
Please follow the rules of posting at this forum, enunciated at:
https://www.freemathhelp.com/forum/threads/read-before-posting.109846/
Please share your work/thoughts and context of the problem (what is the subject topic?) - so that we know where to begin to help you.