Answer:
Center: 
Radius: 
Step-by-step explanation:
It is necessary to remember that the Equation of the circle in Center-radius form, is:

Where the center of the circle is at the point (h, k) and the radius is "r".
Then, given the following equation of the circle:

We can notice that it is written in Center-radius form. Then we can identify that:

Therefore the center is:

And the radius is:

X + y = 8
x - y = 12
--------------add
2x = 20
x = 20/2
x = 10
x + y = 8
10 + y = 8
y = 8 - 10
y = -2
ur numbers are 10 and -2
I will say 36 but I also will say wait on someone else to answer
Answer:
its c hope this helps:)
Step-by-step explanation:
He has 72 books......1/6 are romance
1/6 of 72...." of " means multiply
1/6 * 72 = 72/6 = 12....12 books are romance