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skad [1K]
3 years ago
10

Solve the quadratic equation below by completing the square

Mathematics
2 answers:
tia_tia [17]3 years ago
6 0

Answer:

n = -5/2 and n = 13/2


seraphim [82]3 years ago
5 0

Step-by-step explanation:

4·n^2 - 16·n - 21 = 44

4·n^2 - 16·n = 65

n^2 - 4·n = 65/4

n^2 - 4·n + 4 = 65/4 + 4

(n - 2)^2 = 81/4

n - 2 = ± 9/2

n = 2 ± 4.5

n1 = -2.5 or n2 = 6.5




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Suppose that the probabilities are 0.4, 0.3, 0.2, and 0.1, respectively, that 0, 1, 2, or 3 power failures will strike a certain
defon

Answer:

mean = 1 power failure

variance = 1 (power failure)²

Step-by-step explanation:

Since the mean is computed as

mean = E(x) = ∑ x * p(x) for all x

then for the random variable x=power failures , we have

mean = ∑ x * p(x) = 0 * 0.4 + 1* 0.3 + 2*0.2 + 3* 0.1 = 1 power failure

since the variance can be calculated through

variance =  ∑[x-E(x)]² * p(x) for all x

but easily in this way

variance = E(x²) -  [E(x)]² , then

E(x²) = ∑ x² * p(x) = 0² * 0.4 + 1²* 0.3 + 2²*0.2 + 3²* 0.1 = 2 power failure²

then

variance = 2 power failure² - (1 power failure)² = 1 power failure²

therefore

mean = 1 power failure

variance = 1 power failure²

7 0
3 years ago
How to solve <br>16x&gt;-100<br><br>​
Nikitich [7]

Answer:

x>-25/4

Step-by-step explanation:

7 0
3 years ago
A guitarist sets a goal to practice 200 minutes each week. If he only is going to practice 5 days during the week, which of the
vodomira [7]

Answer:

40

Step-by-step explanation:

40x5=200

200 divided by 5 =40

5 0
3 years ago
The events committee buys 80 flowers for a school dance. The flowers are a combination of carnations and roses. Each carnation c
Slav-nsk [51]

Answer:

64 carnations and 16 roses.

Step-by-step explanation:

The events committee buys 80 flowers

The flowers are a combination of carnations and roses.

Each carnation costs $0.50 and each rose costs $2.50

The committee spends a total of $72

<u>Solution:</u>

<u />

Let there be  (c) carnations and (r) roses.

So,

c + r = 80 flowers

and $0.50c + $2.50 = $72

This forms a simultaneous equation:

c + r = 80 ... (i)

0.5c + 2.5r = 72 ... (ii)

Multiplying equation (i) by 0.5 and equation (ii) by 1 gives;

0.5c + 0.5r = 40 ... (i)

0.5c + 2.5r = 72 ... (ii)

Subtracting (i)  from (ii) gives;

0c + 2r = 32

2r = 32

r = 32 ÷ 2 = 16

Therefore, there are 16 roses

and 80 - 16 = 64 carnations

7 0
3 years ago
An estimated 3 out of every 25 men are left-handed. What percent of men are left-handed?
Annette [7]
3/25=x/100
25x=300
300/25=x
x=12%
4 0
3 years ago
Read 2 more answers
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