Pr act i ce an d Pr o b l em - So l v i n g Ex er ci ses
O PracticeMATHEMATICAL
PRACTICESQ A p p lyIdentify the initial amount a and the growth factor b in each
exponential function.- g(x) = 14 • 2X 10. y = 150 • 1.0894x
- y= 25,600 • 1.01* 12. f[t) = \A t
- College Enrollment The n u m b e r of students enrolled at a college is 15,000 and
grows 4% each year.
a. The initial am o u n t a is.
b. The p ercen t rate of change is 4%, so the growth factor b is 1 +■ = ■.
c. To find the n u m b e r of students enrolled after one year, you calculate
15,000 • ■.
d. C om plete the equ atio n y = to find th e n u m b e r of students enrolled after
x y e a r s.
e. Use your e quation to predict the n u m b e r of stu d en ts enrolled after 25 yr. - Population A population of 100 frogs increases at an an n u a l rate of 22%. How
m any frogs will there be in 5 years? Write an expression to re p resen t the equivalent
monthly population increase rate.
4p See Problem 1.
Find the balance in each account after the given period.- $4000 principal earning 6% co m p o u n d ed annually, after 5 yr
- $12,000 principal earning 4.8% co m p o u n d ed annually, after 7 yr
- $500 p rincipal earning 4% co m p o u n d ed quarterly, after 6 yr
- $20,000 deposit earning 3.5% co m p o u n d ed m onthly, after 10 yr
- $5000 deposit earning 1.5% co m p o u n d ed quarterly, after 3 yr
- $13,500 deposit earning 3.3% co m p o u n d ed m onthly, after 1 yr
- $775 deposit earning 4.25% co m p o u n d ed annually, after 12 yr
- $3500 deposit earning 6.75% co m p o u n d ed m onthly, after 6 m onths
See Problem 2.Identify the initial amount a and the decay factor b in each
exponential function.
y= 5 • 0.5X 24. f{x) = 10 • 0.1x 25. g(x) (^100) (ir
4$) See Problem 3.
y = 0. 1 • 0.9*
Population The p o pulation of a city is 45,000 an d decreases 2% each year. If the
tren d continues, w hat will th e p o pulation be after 15 yr?
State whether the equation represents exponential growth, exponential decay,
or neither.- y = 0.93 • 2X 29. y = 2 • 0.68x 30. y = 68 31. y = 68 • 0.2X
464 Ch ap t er 7 Ex p o n e n t s a n d Ex p o n e n t i a l Fu n c t i o n s