PLS VERY URGENT PLS HELP ME

Which representation has a constant of variation of -2.5

Find the center of the circle that can be circumscribed about efg with e(4,4) f(4,2) g(8,2)

The diameter of a bacteria colony that doubles every hour is represented by the graph below. what is the diameter of the bacteria after 8 hours? graph of a curve passing through the points zero comma 1, one comma two, two comma four, and three comma eight