Answer: 7 × ( 3^n - 1 )
Step-by-step explanation:
This is a geometric progression which has its nth term to be
Tn = ar^n- 1. Now from the question given, the sequence are 7, 21, 63, 189. This is an example of a finite sequence, To find the common ratio, you divide the second term by the first term. So
r = 21/7
= 3. , a = 7
Now to find the nth term put the values in the formula above.
Tn =ar^n-1
= 7(3)^n - 1)
= 7 × ( 3^n - 1 ).
Note, it is not 21^n - 1.
Answer: She started with $160.
It will take 6 weeks before she has less than half of what she originally invested.
Step-by-step explanation:
If her money is decreasing in value by 11% each week, it means that the rate at which it is decreasing is exponential.
We would apply the formula for exponential decay which is expressed as
A = P(1 - r)^t
Where
A represents the value of the investment after t weeks.
t represents the number of weeks.
P represents the initial value of the investment.
r represents rate of depreciation.
From the information given,
A = $142.40
r = 11% = 11/100 = 0.11
t = 1
Therefore
142.40 = P(1 - 0.11)^1
142.40 = P(0.89)
P = 142.4/0.89
P = 160
For her to have half of what she invested originally, then
80 = 160(0.89)^t
80/160 = (0.89)^t
0.5 = (0.89)^t
Taking log of both sides to base 10
Log 0.5 = log0.89^t = tlog0.89
- 0.3010 = - 0.051t
t = - 0.3010/- 0.051
t = 5.9
Approximately 6 weeks
Answer:jjdvdudbufh f
Step-by-step explanation:
<span>Solving for the slope using points ( (−4, 15), (0, 5)</span>
M = ( 15 – 5) / ( -4 – 0) = -5 / 2
Solving for b
<span>
Y = mx + b</span>
5 = 0(-5/2) + b
B = 5
So the linear function is
<span>Y = (-5/2) x + 5</span>
Isolate the x in both cases. What you do to one side, you do to the other.
11x + 4 < 15
Subtract 4 from both sides
11x + 4 (-4) < 15 (-4)
11x < 11
isolate the x, divide 11 from both sides
11x/11 < 11/11
x< 1
x < 1 is your answer for the first one
-------------------------------------------------------------------------------------------------------------------
Again, isolate the x.
12x - 7 > -25
Add 7 to both sides
12x - 7 (+7) > -25 (+7)
12x > -18
Isolate the x, divide 12 from both sides
12x/12 > -18/12
x > -1.5 is your answer for the second one.
-------------------------------------------------------------------------------------------------------------------
hope this helps
