7. because you would put the number set into order from least to greatest first, ti would look like this: 2,3,4,5,9,10,12,12. then go to the middle, crossing one from each side off at one time. Then you get 5 and 9 in the middle. Then the middle between 5 and 9 is seven, you can check this by: 5+9=14, then 14/2= 7.
Your median is 7.
Here you go, hope it helps:)
Standard form of an exponential function is y=ab^x
when x=0, y=3, 3=ab^0, so you can figure out that a=3
when x=-1, y=6, 6=3b^(-1), b^(-1)=2, b=1/2
so the equation is y=3(1/2)^x