To solve an exponential equation, take the log of both sides, and
solve for the variable.
Example 5: Solve for x in the equation
(that's why we choose ). Therefore, the left side of the equation can be simplified to .
is the exact answer.
rounded to 0.6768 is an approximate answer because we rounded.
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
Close enough to 20. Remember it will not check directly because we rounded the answer. If you choose to round to only 2 or 3 decimals, the difference between the check answer and 20 would be greater.
If you would like to review another example, click on Example.
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Author: Nancy Marcus