Answer:
5 out of 9
Step-by-step explanation:
 
        
                    
             
        
        
        
Answer:
Well the answer is 13.3 so 13 years old
Step-by-step explanation:
(F,Y) = (63,21)
Y3=F so F/3=y
so 
F= 40
Y=?
40/3=Y
40/3=13.3
 
        
                    
             
        
        
        
Triangular sequence = n(n + 1)/2
If 630 is a triangular number, then:
n(n + 1)/2  = 630
Then n should be a positive whole number if 630 is a triangular number.
n(n + 1)/2  = 630
n(n + 1)  = 2*630
n(n + 1)  = 1260
n² + n = 1260
n² + n - 1260 = 0
By trial an error note that 1260 = 35 * 36
n² + n - 1260 = 0
Replace n with 36n - 35n
n² + 36n - 35n - 1260 = 0
n(n + 36) - 35(n + 36) = 0
(n + 36)(n - 35) = 0
n + 36 = 0   or   n - 35 = 0
n = 0 - 36,   or  n = 0 + 35
n = -36, or 35
n can not be negative. 
n = 35 is valid.
Since n is a positive whole number, that means 630 is a triangular number.
So the answer is True.
        
             
        
        
        
 The foci need to be equal distances from the center of the eclipse.
See the attached picture. I marked off all the points that were given as choice and from this you can see that that (-5,-4) and  (-5,2) are both 3 units away from the center.
The answer is: (-5,-4) and  (-5,2)