In this lesson, students use logarithms to solve equations that are increasingly more complex. They also learn that we can use logarithms to solve equations with base , and that we refer to such a logarithm as the natural logarithm.

As they solve unfamiliar equations, students practice looking for and making use of structures from more familiar equations (MP7) and attending carefully to the parameters of the equations (MP6). Students also practice constructing logical arguments when they justify their or others’ solutions and explain why a certain value is a reasonable estimate for a given logarithm (MP3).