Answer:
70
-----
20
Step-by-step explanation:
mark me as brilliant
Dur
1 more than 2 times input
input is x
1 more than twice x
1+2x
f(x)=2x+1
Step-by-step explanation:
x - 4 = 2x + 9
x - (2x) = 9 + (4)
-x = 13
x = -13.
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: