It is 4.000 because you can easily look at it and look at 84 the last numbers and it will probably be 4.000 because 84 is above 50 or less so it will go up.
The formula is: f ( x ) = a ( 1/2 )^x + 16 If it passes through the point: ( 1, 8 ) a ( 1/2 ) ^1 + 16 = 8 1/2 a = - 8 a = - 16 Answer: f ( x ) = - 16 ( 1/2 )^x + 16
