Precalculus Algebra - Unit 4 Review

(x-4) / (x^3 + 1) ≥ 0

(−∞,−1)∪[4,∞)

(1) / (x + 4) > −2

(−∞,−9/2)∪(−4,∞)

(x-3) / (x+5) = (x) / (x+2)

-1

(7) / (4x + 1) / (5) = (3x + 7) / (x)

-15 / 8

A colony of bacteria originally contains 300 bacteria. It doubles in size every 30 minutes. How many hours will it take for the colony to contain 3,000 bacteria? (Round your answer to one decimal place.)

1.7 hours

Carbon-14 has a half-life of 5,730 years. A fossil is found that has 18% of the carbon-14 found in a living sample. How old is the fossil? (Round your answer to the nearest year.)

14176 years

A doctor prescribes 200 milligrams of a therapeutic drug that decays by about 10% each hour. To the nearest hour, what is the half-life of the drug?

7 hours

he following equation represents the growth of bacteria in a particular food product, where t represents time in days and f(t) represents the number of bacteria. f(t) = 900e^0.1t The product cannot be eaten after the bacteria count reaches 3,600,000. About how many days will it take before the product is inedible? (Round your answer to the nearest full day.)

82.9404964 round up to 83 days

The temperature T of an object in degrees Fahrenheit after t minutes is represented by the equation T(t) = 62e^−0.0174t + 75. To the nearest degree, what is the temperature of the object after one and a half hours?

87.95049983 round up to 88°F

Which of the following are not models of exponential decay? (Select all that apply.) h(x) = 50 − x f(x) = 500 · 16x Q(x) = 3(0.3)x P(x) = (0.7x)2

h(x) = 50 − x P(x) = (0.7x)2