91Ó°ÊÓ

Use the formula \(A=P e^{r t}\). How much should Leroy invest now at \(7.2 \%\) compounded continuously so that the account contains \(\$ 8000\) in 12 yr?

Write as a single logarithm. Assume the variables are defined so that the variable expressions are positive and so that the bases are positive real numbers not equal to \(1 .\) $$3 \log a+4 \log c-6 \log b$$

Solve each logarithmic equation. $$\log _{(y-1)} 4=2$$

The value, \(V(t),\) in dollars, of a compact car \(t\) yr after it is purchased is given by $$V(t)=10,150(0.784)^{t}$$ a) What was the purchase price of the car? b) What will the car be worth 5 yr after purchase?

Evaluate each logarithm. $$\log _{5} 25$$

Use the formula \(A=P e^{r t}\). Raj wants to invest \(\$ 3000\) now so that it grows to \(\$ 4000\) in 4 yr. What interest rate should he look for? (Round to the nearest tenth of a percent.)

Use the change-of-base formula with either base 10 or base \(e\) to approximate each logarithm to four decimal places. $$\log _{9} 70$$

The value, \(V(t),\) in dollars, of a minivan \(t\) yr after it is purchased is given by $$V(t)=16,800(0.803)^{t}$$ a) What was the purchase price of the minivan? b) What will the minivan be worth 6 yr after purchase?

Write as a single logarithm. Assume the variables are defined so that the variable expressions are positive and so that the bases are positive real numbers not equal to \(1 .\) $$\log \left(r^{2}+3\right)-2 \log \left(r^{2}-3\right)$$

Use the change-of-base formula with either base 10 or base \(e\) to approximate each logarithm to four decimal places. $$\log _{3} 52$$