Lucy wants to be exempt from her semester exam. In order for that to happen, she has to average an 85 over 3 test grades. Her first 2 test grades were 81 and 86. What does Lucy need to make on her third test in order to have an exact average of 85 and be exempt from her exam?

Solve the system. -a+4b+2c=-8 3a+b-4c=9 b=-1 a.(0,11) ,-1,2) c.(1,1,-2) d.(2,-1,-1)

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?

The sum of two numbers is 86, and their difference is 20. find the two numbers