QuantumPerihelion

Curious because I recently read about it.

http://www.physicsclassroom.com/class/circles/Lesson-4/Kepler-s-Three-Laws

I'm really not getting Kepler's laws, so I have four different questions about how binary star systems work. First, say there is a binary system that consists of two white dwarfs in circular orbits with an orbital period of 60 days. Is it even possible yo find the maximum distance between the two white dwarfs? Next, If one of the white dwarfs is twice as massive as the other, what is the approximate maximum orbital radius of the smaller star? Next, If the angular separation of the two white dwarfs is measured (I don't know how) to be 0.013 arcseconds(the system is viewed face-on). If the stars were estimated to have equal masses of 0.8 MSun each, approximately how far away would the system be? Lastly, if the mass ratio of the two white dwarfs were 3:1 and the distance between them were 0.15 AU, what would be the approximate radius of the more massive star's orbit? Not sure if this should go to homework help because it's just some problems I got from the internet, but any help would be greatly appreciated.

So then after a few steps 16x - 25 = 23 16x = 48 x = 3

So suppose f(x) = 4x - 5. Solve f(f(x)) = 23 for x. I have no idea how to solve what I think is a function of a function, as I am new to this type of "basic" algebra problem. Not a homework problem just trying to learn new things from some things I found online.