Answer:
:)
Step-by-step explanation:
For simplicity I will substitue  for β.
 for β.

In the first step I used the identity
 
 
And I factored out 
Then it's just simple algebra to cancel till the 3rd step where we used another identity derived from the Pythagorean Theorem.

That's it!
 
        
             
        
        
        
A. Frank has 24 marbles. I found this because Dan has 15 and total is 63 so subtract 63-15= 48. 48 divided by 2 people, which are Ellie ans Dan is 24. Dan has 24 marbles.
        
             
        
        
        
We know that: 

is an equation of a circle.
When we substitute x and y (from the pairs we have), we'll get a system of equations:

and all we have to do is solve it for a, b and r.
There will be:

From equations (II) and (III) we have:

and from (I) and (II):

Now we can easly calculate a and b:

Finally we calculate 

:

And the equation of the circle is:
 
 
        
        
        
64 
8x8 size bored 
That’s is your answer
 Thanks jaddan.