Answer:
i think the second answer
Step-by-step explanation:
Answer:
(3, -3)
Step-by-step explanation:
When asked to solve by elimination, you put them on top of one another, like you're going to add it.
10x + 7y = 9
-4x - 7y = 9
See that 7y? You can cancel those out because one is negative, and one is positive. So those are gone. You finish adding the rest of the numbers as usual and solve for x.
6x = 18
x = 3
Take x, and plug it into either equation to find y.
10(3) + 7y = 9
7y = -21
y = -3
(3, -3)
Hope this helped!
Answer:
The rate at which the distance between them is changing at 2:00 p.m. is approximately 1.92 km/h
Step-by-step explanation:
At noon the location of Lan = 300 km north of Makenna
Lan's direction = South
Lan's speed = 60 km/h
Makenna's direction and speed = West at 75 km/h
The distance Lan has traveled at 2:00 PM = 2 h × 60 km/h = 120 km
The distance north between Lan and Makenna at 2:00 p.m = 300 km - 120 km = 180 km
The distance West Makenna has traveled at 2:00 p.m. = 2 h × 75 km/h = 150 km
Let 's' represent the distance between them, let 'y' represent the Lan's position north of Makenna at 2:00 p.m., and let 'x' represent Makenna's position west from Lan at 2:00 p.m.
By Pythagoras' theorem, we have;
s² = x² + y²
The distance between them at 2:00 p.m. s = √(180² + 150²) = 30·√61
ds²/dt = dx²/dt + dy²/dt
2·s·ds/dt = 2·x·dx/dt + 2·y·dy/dt
2×30·√61 × ds/dt = 2×150×75 + 2×180×(-60) = 900
ds/dt = 900/(2×30·√61) ≈ 1.92
The rate at which the distance between them is changing at 2:00 p.m. ds/dt ≈ 1.92 km/h
Answer:
a) We need a sample size of at least 2401.
b) We need a sample size of at least 1936.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of , and a confidence level of , we have the following confidence interval of proportions.
In which
z is the zscore that has a pvalue of .
The margin of error is:
95% confidence level
So , z is the value of Z that has a pvalue of , so .
(a) you are unwilling to predict the proportion value at your school and
We use , which is when we are going to need the largest sample size.
So we need to find We need a sample size of at least 2401.
(b) you use the results from the surveyed school as a guideline.
Now the same calculation, just with . So
We need a sample size of at least 1936.
Answer:
a₂ = -3
a₃ = -1
Step-by-step explanation:
We have to insert two arithmetic means between -5 and 1
Let a₁ and b₂ be the two arithmetic means between -5 and 1
-5, a₂, a₃, 1
Here,
We know that the nth term of an Arithmetic sequence
aₙ = a₁ + (n-1)d
a₄ = -5 + (4-1)d
1 = -5 + 3d
1 + 5 = 3d
3d = 6
Dividing both sides by 2
d = 2
Also
a₂ = a₁ + (2-1)d
a₂ = -5 + d
a₂ = -5 + 2 ∵ d = 2
a₂ = -3
a₃ = a₁ + (3-1)d
a₃ = -5 + 2d
a₃ = -5 + 2(2) ∵ d = 2
a₃ = -5 + 4
a₃ = -1
Thus,
a₂ = -3
a₃ = -1
Thus, the sequence becomes:
-5, -3, -3, 1
