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:
Answer: 8 movies
12 + 1.50x = 3x
Move the variables to one side
12 = 1.50x
Isolate x
8 = x
Check:
3(8)= 24
12.00 + 1.50(8) = 24
The answer to this equation is: 7q +12
The line passing through (3, -1) and (-1, 5) has this slope:
5+1
m = ---------- = -3/2
-1-3
We need to find the y-intercept. To do this, substitute the knowns (-3/2 for m, -1 for y and 3 for x) into the slope-intercept equation:
-1 = (-3/2)(3) + b. Then: -1 = -9/2 + b, and so b = 9/2 - 1 = 7/2.
The desired equation is y = (-3/2)x + 7/2.
Greater because a centimeter is smaller than an inch.