X=5, y=-4
(5,-4)
do you need the work?
Answer:
C. The 6th term is positive/negative 80
Step-by-step explanation:
Given
Geometric Progression


Required

To get the 6th term of the progression, first we need to solve for the first term and the common ratio of the progression;
To solve the common ratio;
Divide the 7th term by the 5th term; This gives

Divide the numerator and the denominator of the fraction by 40
----- equation 1
Recall that the formula of a GP is

Where n is the nth term
So,


Substitute the above expression in equation 1
becomes


Square root both sides

r = ±
Next, is to solve for the first term;
Using 
By substituting 160 for T5 and ±
for r;
We get


Multiply through by 16



Now, we can easily solve for the 6th term
Recall that the formula of a GP is

Here, n = 6;



r = ±
So,
or 
or 
or 
±80
Hence, the 6th term is positive/negative 80
Answer:
190
Step-by-step explanation:
Data provided in the question:
Confidence level = 99%
Therefore,
α = 1% = 0.01
[ from standard normal table ]
z-value for
= 2.58
Margin of error, E = $0.06
Standard deviation, σ = $0.32
Now,
n = 
Here,
n is the sample size (or the minimum number of gas stations )
on substituting the respective values, we get
=
=
= 13.76²
= 189.3376 ≈ 190
Hence,
minimum number of gas stations that she should include in her sample is 190
Answer:
x=-6 y=-26
Step-by-step explanation:
in the first is -4 every time, in the second is -20 every time