I'm getting confused on how to find the greatest common factor. Please help? A step by step process would be help full and how you found the GCF.

Simplify (a/b - b/a) times (a - a^2/a+b) a - a^2/a=b is a mixed number

Karen is financing $291,875 to purchase a house. she obtained a 15/5 balloon mortgage at 5.35%. what will her balloon payment be? a. $220,089.34 b. $219,112.46 c. $246,181.39 d. $230,834.98

Any is very appreciated! (picture is provided below)not sure how to do this at all won't lie