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yKpoI14uk [10]
3 years ago
11

Is f(x)=-4x squared -2x-8, concave up or down

Mathematics
1 answer:
yKpoI14uk [10]3 years ago
3 0
Squared, so it is a parabola

leading coefieint (-4) is negative, so it opens down

it is concave down
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A boat is being pulled into a dock with a rope attached to the boat at water level. When the boat is 12 feet from the dock, the
Natali5045456 [20]

Given :

A boat is being pulled into a dock with a rope attached to the boat at water level. When the boat is 12 feet from the dock, the length of the rope form the boat to the dock is 3 feet longer than twice the height of the dock above the water.

To Find :

The height of the dock.

Solution :

This will make a right angle triangle as given in link below .

Now , applying Pythagoras theorem :

(2h+3)^2=h^2+12^2\\\\4h^2+9h+9=h^2+144\\\\h^2+4h-45=0\\\\(h-5)(h+9)=0

Now , h = 5 or h = -9 .

Now , height cannot be negative .

So , height of the dock is 5 ft .

Hence , this is the required solution .

8 0
3 years ago
Solve this PLZ!<br> 4 - 7 (v - 9) = -7 -6(v - 10)
Arisa [49]
I maybe wrong, but I think it is 14

Simplify both sides of the equation
(Do distributive property)
Add 6v to both sides
Subtract 67 from both sides
Divide both sides by -1
7 0
3 years ago
A random sample of 100 workers in one large plant took an average of 12 minutes to complete a task, with a standard deviation of
SCORPION-xisa [38]

Answer:

The 95% Confidence Interval for the difference between the two population mean completion times =

(0.081, 1.919)

Step-by-step explanation:

Confidence Interval for difference between two means =

μ1 -μ2 ± z × √ σ²1/n1 + σ²2/n2

Where

μ1 = mean 1 = 12 mins

σ1 = Standard deviation 1 = 2 mins

n1 = 100

μ2= mean 2 = 11 mins

σ2 = Standard deviation 2 = 3 mins

n1 = 50

z score for 95% confidence interval = 1.96

μ1 -μ2 ± z × √ σ²1/n1 + σ²2/n2

= 12 - 11 ± 1.96 × √2²/100 + 3²/50

= 1 ± 1.96 × √4/100 + 9/50

= 1 ± 1.96 × √0.04 + 0.18

= 1 ± 1.96 × √0.22

= 1 ± 1.96 × 0.469041576

= 1 ± 0.9193214889

Confidence Interval

= 1 - 0.9193214889

= 0.0806785111

≈ 0.081

1 + 0.9193214889

= 1.9193214889

≈ 1.919

Therefore, the 95% Confidence Interval for the difference between the two population mean completion times =

(0.081, 1.919)

5 0
3 years ago
The Taylors have purchased a $320,000 house. They made an initial down payment of $20,000 and secured a mortgage with interest c
gogolik [260]
Part A: monthly payment

Initial loan after downpayment,  
P = 320000-20000= 300,000

Interest rate per month, 
i = 0.06/12= 0.005

Number of periods, 
n = 30*12= 360

Monthly payment, 
A = P*(i*(1+i)^n)/((1+i)^n-1)
= 300000(0.005(1.005)^360)/(1.005^360-1)
= 1798.65


Part B: Equities
Equity after y years
E(y) = what they have paid after deduction of interest
= Future value of monthly payments - cumulated interest of net loan
= A((1+i)^y-1)/i - P((1+i)^y-1)
= 1798.65(1.005^y-1)/.005 - 300000(1.005^y-1)
= (1798.65/.005-300000)(1.005^y-1)

Equity E
for y = 5 years = 60 months
    E(60) = (1798.65/.005-300000)(1.005^60-1) = 18846.17
for y = 10 years = 120 months
    E(120) = (1798.65/.005-300000)(1.005^120-1) = 45036.91
y = 20 years = 240 months
    E(240) = (1798.65/.005-300000)(1.005^240-1) = 132016.53

Check: equity after 30 years
y = 30 years = 360 months
    E(360) = (1798.65/.005-300000)(1.005^360-1) = 300000.00  .... correct.
3 0
3 years ago
Read 2 more answers
Two beakers plus their contents have a mass of 180.4 grams. The total mass of the contents is 56.8 grams. Write and solve an equ
Anika [276]
I don't know if I am right but I think this is the answer:
If we write beaker with x and content with y
then y=56.8/2=28.4   this is the content of one beaker
so there are two beakers:
2x+28.4=180.4
2x=180.4-28.4
2x=152/2
x=76   
6 0
3 years ago
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