Question

Kinda confused on this one, someone help please!

Answer 1

To determine which type of graph this is, look at the estimated population, and look at the differences between each point:

89, 55, 34, 21, 13

Differences: 34, 21, 13, 8

The differences are all different values, so linear can be removed.

Because the graph is decreasing at a rate, we can eliminate both quadratic answers, as they would have increasing values.

The answer is 'exponential; y = 89 * 0.62^x'.

Answer 2

As x increases from 0 to 1, y decreases from 89 to 55. This could happen if 89 were multiplied by the rate of change factor 0.62: 0.62(89) = 55. Likewise, if we mult. 55 by 0.62, we get 34, which also agrees with the table values for y.

Thus, this is an example of exponential decay, with decay constant 0.62.