# Lesson 4Log-Arithm-eticPractice Understanding

### 1.

Factor out the greatest common factor in the expression. Then simplify the numbers inside the parentheses.

Factor out the GCF

Factored Form

Simplified Expression

### 2.

Jaxon has invested in an excellent money market account that earns per year. Given is a chart of his year-end balances that appeared on his investment statements.

Beginning Balance

End of year

End of year

End of year

Jaxon’s money is growing exponentially, and he recalls from a previous math class that the formula for an exponential function is . He recalls that and . He thinks should equal , but that number isn’t giving him the numbers on his bank statement. What number should he be using for ? Explain.

### 3.

Jackie owes on a loan. She has agreed to pay the loan company of the outstanding balance on the first day of each month. Given is a chart of the balances she owes after each payment.

Initial Amount Owed

Month 1

Month 2

Month 3

Jackie knows her loan balance is decreasing exponentially. She also recalls from a previous math class that the formula for an exponential function is . She replaces with and lets be the number of monthly payments. But when she uses in the formula for , it doesn’t give her the correct balance for each month. What number should she be using for ? Explain.

## Set

Use properties of logarithms to rewrite the indicated logarithms in terms of the given values, then find the indicated logarithm using the given approximate values.

Do not use a calculator to evaluate the logarithms.

Given:

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## Go

Use your calculator and the definition of to find the value of . (Round your answers to four decimals.)