To solve an exponential equation, take the log of both sides, and
solve for the variable.
Example 7: Solve for x in the equation
Solution:
is the exact answer and is the approximate answer.
Check: Let's check the approximate answer with the original problem. When we substitute the above value of x in the left side of the equation, we get
You can also check your answer by graphing the function
and note where the graph crosses the x-axis. If you have worked the problem correctly, it should be the same value of x.
If you would like to review another example, click on Example.