If you can rewrite the formula as (x-a)² + (y-b)² = r², the center is at (a,b) and the radius is r.
If you work out this equation, and map it to the original, you will find that the +4x term hints that a = 2 (double product) and -12y hints that b=-6, and r=6.
So, the formula can be written as (x+2)² + (y-6)² = 6² and the center is at (-2,6) and the radius is 6.
Answer:
<em />
<em />
<em />
Step-by-step explanation:
Given
$1000 for 9 days
$750 for 10 days
$850 for 4 days
$900 for other days
Required
Compute the daily average
First, we need to compute the number of days her balance is $900
Assuming the billing cycle is 30 days;



The Average is then calculates using:




<em />
<em> --- Approximated</em>