0 1 1 3
2 9
3 2
7 4
8 1
Write a linear (y = m x + b ), quadratic (y = a x 2 ), or exponential (y = a ( b ) x ) function that models the data.

The x-values are increasing by 1 each time and the y-values are doubling each time. Since the y-values are increasing by a constant factor of 2, the model must be exponential. The data would have to increase by a constant amount to be linear and the second difference of the y-values would have to be constant for the model to be quadratic.

Notice that each y-coordinate is a power of 2. Since 2=21,4=22,8=23,16=242=21,4=22,8=23,16=24, and 32=2532=25, then each y-coordinate is a power of 2 where the exponent is the x-coordinate. The equation is then y=2xy=2x.

I hope it will help you

The answer is B y: begins at 4, multiply by 1/2