CC Algebra 2H
HW#______ Name___________________________________
Worksheet 4-5X
Exponential Equations and Review
Date__________________Per_____Col_____
Solve for x. For #1-5, give exact answers in simplest form (no decimals). For #6-9, give an exact
answer in terms of logs and an approximate decimal answer rounded to the nearest hundredth.
1
1. 2 x  6  8 x
2. 27 2 x  1  9 x  2
3. 4 1  x 
8
1
4.  
5
x2
 125
x
2
7. 5 x  2  200
Answers: 1. 3
2.
7
4
3.
5
2
x
5. 216 3  36 2 x  3
6. 7 x  56
8. 30  x  5
9. 3 2 x  5  1  8
4.
4
5
5. -2
6. 2.07
7. 5.29
8. -.47
9. 3.39
For # 10- 14, solve for x and give answers in simplest form (no decimals).
x
10. log 3 x 2  log 2 16
12. log 3  10 x  3 2  10
11. 2  log 3x  log
12
13. log  4 x 1   log 6 x  log  5x  2   log 8x
14. 2 log3  x  2   4
15. A new car costs $24,000 and decreases in value each year by 10%. The car’s yearly value can be
modeled by the function V t   24000 0.9  t , where t is the number of years since the car was
purchased.
a) To the nearest dollar, what will the
b) To the nearest tenth of a year, after how many years
value of the car be after 4 years?
will the car’s value be only half of its original value?
Answers: 10. ± 9
11. 20
CC Alg2H WS 4-5X F2014
12. 24
13. 2
14. 7
15. a) $15, 746
b) 6.6 yrs