Algebra 1: Concepts and Skills

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Chapter 8 : Exponents and Exponential Functions
8.6 Exponential Growth Functions

#### 8.6 Problem Solving Help

Help for Exercises 33 and 34 on page 480

In Exercise 33, be careful not to confuse growth factor with growth rate. Growth factor is usually given as a number greater than 1, and it describes the factor by which something increases per time interval. Growth rate describes the percent change per time interval, written in decimal form. To illustrate this concept, consider something with an initial amount of 3, that doubles every year. The first five years yield the sequence of numbers 3, 6, 12, 24, 48. The growth factor in this case is 2 (since the value doubles with each time period). The growth rate is the percent increase. A quantity that doubles increases by 100%, which is written in decimal form as 1. (any value and its preceding value can be used to find growth rate). And remember that if the growth rate is r, then the growth factor is 1 + r.

In Exercise 34, use the fact that there are 7 time intervals during which the mola mola's length triples. You can write an equation based on this information, and substitute the original length to find the maximum length of an adult mola mola.