A certain circle can be represented by the following equation. x^2 + y^2 + 12x + 4y + 15 = 0
What is the center of this circle ?
What is the radius of this circle ?

Mexico city, mexico, is the world's second largest metropolis and is also one of its fastest-growing cities with a projected growth rate of 3.2% per year. its population in 1991 was 20,899,000 people. use the formula p = 20.899e0.032t to predict its population p in millions with t equal to the number of years after 1991. what is the predicted population to the nearest thousand of mexico city for the year 2010?

School has 204 sixth grade students. if the sixth grade is 30% of the total school, how many students are in the middle school?

Explain why the factor 1.5 is broke. into two numbers in the model.