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2 years ago

Solve 2x2 + 20x + 8 = 0 by completing the square.

Mathematics

2 answers:

Elodia [21]2 years ago

3 0

Answer:

Answer B:

Step-by-step explanation:

just took the test)))):

sammy [17]2 years ago

3 0

the answer: B

ok done. Thank to me :>

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If 90 percent of automobiles in Orange County have both headlights working, what is the probability that in a sample of eight au

Alex17521 [72]

Answer:

$P(X \geq 7) = P(X=7) +P(X=8)$

And we can find the individual probabilities using the probability mass function

$P(X=7)=(8C7)(0.9)^7 (1-0.9)^{8-7}=0.3826$

$P(X=8)=(8C8)(0.9)^8 (1-0.9)^{8-8}=0.4305$

And replacing we got:

$P(X \geq 7) = P(X=7) +P(X=8)=0.3826 +0.4305=0.8131$

Step-by-step explanation:

Previous concepts

The binomial distribution is a "DISCRETE probability distribution that summarizes the probability that a value will take one of two independent values under a given set of parameters. The assumptions for the binomial distribution are that there is only one outcome for each trial, each trial has the same probability of success, and each trial is mutually exclusive, or independent of each other".

Solution to the problem

Let X the random variable of interest "number of automobiles with both headligths working", on this case we now that:

$X \sim Binom(n=8, p=0.9)$

The probability mass function for the Binomial distribution is given as:

$P(X)=(nCx)(p)^x (1-p)^{n-x}$

Where (nCx) means combinatory and it's given by this formula:

$nCx=\frac{n!}{(n-x)! x!}$

And for this case we want to find this probability:

$P(X \geq 7) = P(X=7) +P(X=8)$

And we can find the individual probabilities using the probability mass function

$P(X=7)=(8C7)(0.9)^7 (1-0.9)^{8-7}=0.3826$

$P(X=8)=(8C8)(0.9)^8 (1-0.9)^{8-8}=0.4305$

And replacing we got:

$P(X \geq 7) = P(X=7) +P(X=8)=0.3826 +0.4305=0.8131$

3 0

2 years ago

Read 2 more answers

The average age of staff in the maths department is 40.

pashok25 [27]

Answer:

Cerian is 28 years old

Step-by-step explanation:

The given parameters are;

The average age of the staffs in the mathematics department = 40

The number of staffs in the department = 7

The average age of Jill, Nicky and Wendy = 41

The average age of Andy, Alan and Cathy = 43

From the given parameters, we have;

The average age of the staffs in the mathematics department = (The sum total of the ages of the members of the math department)/(The number of staffs in the department)

Therefore;

40 = (The sum total of the ages of the members of the math department)/ (7)

From which we have;

The sum total of the ages of the members of the math department = 40 × 7 = 280

Which gives;

Jill's age + Nicky's age + Wendy's age + Cathy's age + Cerian's age + Alan's age + Andy's age = 280 years

The average age of Jill, Nicky and Wendy = 41

Given that Jill, Nicky, and Wendy make up 3 of the 7 members of staffs, we have;

The average age of Jill, Nicky and Wendy = (The sum total of the ages of Jill, Nicky, and Wendy)/(The number of staff Jill, Nicky, and Wendt make)

Therefore;

The sum total of the ages of Jill, Nicky, and Wendy = 41 × 3 = 123

Which gives;

Jill's age + Nicky's age + Wendy's age = 123 years

Similarly, the sum total of the ages of Andy, Alan, and Cathy = 43 × 3 = 129

Which gives;

Andy's age + Alan's age + Cathy's age = 129 years

Therefore;

Cerian's age = (Jill's age + Nicky's age + Wendy's age + Cathy's age + Cerian's age + Alan's age + Andy's age) - (Jill's age + Nicky's age + Wendy's age) + (Andy's age + Alan's age + Cathy's age)

∴ Cerian's age = 280 years - 123 years - 129 years = 28 years

6 0

3 years ago

This question made me stuck lol.. I really need help

Svetach [21]

(4,5)(2,1)
slope = (1 - 5) / (2 - 4) = -4/-2 = 2

(-2,3)(-4,4)
slope = (4 - 3) / (-4 - (-2) = 1/(-4 + 2) = -1/2

2 and -1/2 are negative reciprocals of each other....therefore, ur lines are perpendicular <==

5 0

3 years ago

Solve the equation-54-9g

coldgirl [10]

-68hen you enter an equation into the calculator, the calculator will begin by expanding (simplifying) the problem.

4 0

3 years ago

The falcons basketball team beat the tigers by 7 points in a game. The total points scored by both teams was 83. Write and solve

Blizzard [7]

Falcons = 45
Tigers = 38

83-7=76
76/2=38 (Tigers)
38+7=45 ( Falcons)

6 0

3 years ago