The formula for the equation of a circle is (x - h)² + (y - k)² = r² 
where (h, k) is the center of the circle and <em>r</em> is the radius.
So we need to find the values of (h, k) in order to find the center of the circle.
If we simply line up the equation of our given circle with our formula,
we can see that -h = 3 or h = -3 and -k = -2 so k = 2.
So now we have our answer.
center ⇒ (-3, 2)
 
        
             
        
        
        
1 inch = 2.54 cm
 so multiply 27 by 2.54
27 x 2.54 = 68.58 cm long
 
        
             
        
        
        
Let's let the weight of a large box be L, and the weight of a small box be S.
We know that 5 large boxes and 3 small boxes is 120kg, so:
5L + 3S = 120
We also know that 7 large boxes and 9 small boxes is 234kg, so:
7L + 9S = 234
You can multiply the first equation by 3 to get:
15L + 9S = 360
See how now both equations have 9S? We can now subtract one from the other:
(15L+9S) - (7L+9S) = 360-234
8L = 126
L = 15.75
Now sub this value back into an equation:
(5x15.75) + 3S = 120
3S = 41.25
S = 13.75
Double check these values
(7x15.75) + (9x13.75) 
= 110.25 + 123.75
=234, which is consistent with above.
So a large box is 15.75kg, and a small box is 13.75kg.
Hope this helped
        
             
        
        
        
<span> commutative property</span>
        
             
        
        
        
DE + EF = DF
x - 2 + 6x + 4 = 8x - 2
7x + 2 = 8x - 2
2 + 2 = 8x - 7x
4 = x <===