Answer:
The possible number of CDs she could buy is 1, 2, and 3.
Step-by-step explanation:
First, you have to make an equation to solve to find the answer(s):
- 80 - (18 · x) ≥ 20
- 80 is how much money Felicia has; 18 is for the cost of each CD; x is for the number of CDs; ≥ is no less; and 20 is how much money Felicia needs to have left.
1.) 80 - (18 · 1) ≥ 20
80 - 18 · 1 ≥ 20
80 - 18 ≥ 20
62 ≥ 20
Since 62 ≥ 20 is always true, there are infinitely many solutions.
2.) 80 - (18 · 2) ≥ 20
80 - 18 · 2 ≥ 20
80 - 36 ≥ 20
44 ≥ 20
Since 44 ≥ 20 is always true, there are infinitely many solutions.
3.) 80 - (18 · 3) ≥ 20
80 - 18 · 3 ≥ 20
80 - 54 ≥ 20
26 ≥ 20
Since 26 ≥ 20 is always true, there are infinitely many solutions.
4.) 80 - (18 · 4) ≥ 20
80 - 18 · 4 ≥ 20
80 - 72 ≥ 20
8 ≥ 20
Since 8 ≥ 20 is false, there is no solution.
5.) 80 - (18 · 5) ≥ 20
80 - 18 · 5 ≥ 20
80 - 90 ≥ 20
- 10 ≥ 20
Since - 10 ≥ 20 is false, there is no solution.
Answer:
2998 ; 17%
Step-by-step explanation:
Given the function:
t(c)=-3970.9(ln c)
c = % of carbon remaining ; t = time
1.) c = 47% = 47/100 = 0.47
t(0.47) = - 3970.9(In 0.47)
t = - 3970.9 * −0.755022
t = 2998.119
t = 2998
B.)
t = 7000
t(c)=-3970.9(ln c)
7000 = - 3970.9(In c)
7000 / - 3970.9 = In c
−1.762824 = In c
c = exp(−1.762824)
c = 0.1715596
c = 0.1715596 * 100%
c = 17.156% ; c = 17%
Answer:
(4 + 7i)(4 – 7i)
Step-by-step explanation:
This pair will produce a real answer because they are complex conjugates.
Complex conjugates ( a+bi) (a-bi) when multiplied together form a real number ( a^2 + b^2)
