PartialMathematician

"F" could also be an altitude, median, or perpendicular bisector...we really need an image to help you. 

I am guessing "F" is the incenter of the triangle. (i think I've seen and solved this problem before...). But just to clarify, could you please send an image?

Yea, the "I'am not a robot" tag has an extra apostrophe or extra "a". My Grammarly senses it. 

StackExchange...huh...I answered some questions there about computer science. I didn't know they also had a math webpage.  

Please limit your questions to "math-related" questions. If you have a question that is not "math-related", you can tag your question as "off-topic" to allow other math questions to take priority. Please do not advertise products on this website...we are specialized in answering math questions only. 

If you have nowhere to post this "fat-burning" advertisement, please post your message somewhere else on social media. 

With best regards,

- PartialMathematician (Not PartialFatBurner)

We could also substitute \(y^2\) for \(x\), so we have \(16-25y^2\). Now, this looks looks like a difference of squares. We can factor it into \((4+5y)\cdot(4-5y)\). Substituting back \(x\) for \(y^2\), we have \(\boxed{(4+5\sqrt{x})\cdot(4-5\sqrt{x})}\). 

Hope this helps,

- PartialMathematician

#3 could be factored into \(4^2 - 5^2(x)\)

Composing answer soon...

Please limit your questions to math questions. We will be happy to help you.

How long are these answers supposed to be, CPhill and Melody? I spent over 20 minutes writing this much. I am not sure what the average time spent answering a difficult question is, so I am going to assume 20 minutes is not too long. Thank you for clarifying. 

- PartialMathematician