Exponential Equations

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SWBAT solve exponential equations by using properties of exponents.

Big Idea

We can solve some exponential equations by rewriting both sides of the equation as a power of the same base.

Warm Up

30 minutes

As a warm-up, I ask my students to complete Warm up Exponential Equations.docx, which is a collection of equations in which the variable is an exponent.  Although they have probably not seen exponential equations before, they can solve this specialized set by working backwards from the properties of exponents.  I like this this warm up because it provides much-needed practice on applying the properties of exponents and also helps students see why they needed to learn new properties!

Discussion and Guided Instruction

45 minutes

When my students have completed the warm-up, I ask volunteers to come to the board to demonstrate their solution to some of the more difficult equations.  We discuss the different approaches students used and take time to record some strategies for solving exponential equations.  Most importantly, I want them to see that writing both sides of an equation as a power of the same base can be a very efficient method of solving exponential equations.  

I will ask my students to include in their notebooks 4 problems, three of which can be solved with the strategy outlined above.  The fourth problem cannot be solved in this way (because the solution is irrational) and I ask them to identify the problem they cannot solve.   

Practice and Assignment

20 minutes

Students will take time to work individually on WS Solving Exponential Equations.docx.  This is a collection of equations that are slightly more challenging than the ones we discussed in the warm up.  I assign this set in class so that students have the opportunity to ask questions of each other or me.  

For homework students will complete  WS Solving Exponential Equations.docx.