# Exponential and Logarithmic Equations

**Solving Exponential Equations**

Example 1: Solve 3^{x}=20. Round your answer to four decimal places.

Example 2: Solve for x to four decimal places.

Example 3: A certain amount of money P (principal) is invested at an annual rate r compounded annually. The amount of money A in the account after t years, assuming no withdrawals, is given by

How many years to the nearest year will take the money to double if it is invested at 6% compounded annually?

Example 4: The atmospheric pressure P, in pounds per square inch, at x miles above sea level is given approximately by

At what height will the atmospheric pressure be half the sea-level pressure? Compute the answer to two significant digits.

**Solving Logarithmic Equations**

**Example 6:** Solve

Example 7: Solve and check.

*Note:

Example: Solve:

Example: Solve:

Example: Solve: