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Hunter-Best [27]
3 years ago
14

If a polynomial function f(x) has roots -8, 1, and 6i, what must also be a root of f(x)?

Mathematics
1 answer:
Naddik [55]3 years ago
5 0

Answer:

it must also have the root : - 6i

Step-by-step explanation:

If a polynomial is expressed with real coefficients (which must be the case if it is a function f(x) in the Real coordinate system), then if it has a complex root "a+bi", it must also have for root the conjugate of that complex root.

This is because in order to render a polynomial with Real coefficients, the binomial factor  (x - (a+bi)) originated using the complex root would be able to eliminate the imaginary unit, only when multiplied by the binomial factor generated by its conjugate: (x - (a-bi)). This is shown below:

(x-(a+bi))*(x-(a-bi))=\\(x-a-bi)*(x-a+bi)=\\([x-a]-bi)*([x-a]+bi)=\\(x-a)^2-(bi)^2=\\(x-a)^2-b^2(-1)=\\(x-a)^2+b^2

where the imaginary unit has disappeared, making the expression real.

So in our case, a+bi is -6i (real part a=0, and imaginary part b=-6)

Then, the conjugate of this root would be: +6i, giving us the other complex root that also may be present in the real polynomial we are dealing with.

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The perimeter you just add everything up so it’s 65cm
15+13+4+7+9+4+13
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The question is relating Rhonda's distance travelled and time taken

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1 year ago
Carlo wants to join gym.the total gym offers three options for the membership. Option1:pay as you go.pay only $6 each time You w
Ray Of Light [21]
The question is attached in the image.

1- Carlo thinks he will go to the gym 20 times this month. Calculate how much each of these options will cost Carlo for one month.
a- Pay as you go:
Total cost = 6 * 20 = $120
b- Regular deal:
Total cost = 50 + 2(20) = 50 + 40 = $90
c- All-in-one-price:
Total cost = $100
d- The least expensive for Carlo in this case would be the regular deal.

2- How many visits each month would make the cost of the Regular-Deal and the All-in-one the same?
Assume number of visits is x.
Regular deal = All in one
50 + 2x = 100
2x = 100 - 50
2x = 50
x = 25 visits

3a- It costs $300 to join the new Superfit Gym. You then pay $15 each month and $2 each time you work out. Carlo thinks he will use the gym 20 times each month for a year.
Calculate the cost of the Superfit gym for one year.
Total cost = initial payment + 15*number of month + 2*days of workout
initial payment = $300
15*number of months = 15 * 12 = $180
2*days of workout = 2*20*12 = $480
Total cost = 300 + 180 + 480 = $960

3b- How much will Carlo save during the first year if he uses the Superfit gym rather than the regular deal at the other gym?
First we will calculate the total cost of one year using the regular deal at the other gym as follows:
Total cost at other gym = monthly cost + cost of each workout
Total cost at other gym = 50(12) + 2(12)(20) = $1080
Then, we will calculate the difference to know the amount Carlo would save as follows:
Carlo would save = 1080 - 960 = $120

Hope this helps :)

7 0
3 years ago
What percent of 72 is 9? 1/8% 1 1/4% 12 1/2% 125%
USPshnik [31]

Answer:

12\dfrac 12\%

Step by step explanation:

\text{Let it be}~ x\%,\\\\~~~~~72 \cdot x \% = 9\\\\\\\implies 72\cdot \dfrac{x}{100} = 9\\\\\\\implies x = \dfrac{9 \times 100}{72}\\\\\\\implies x = \dfrac{100}{8}\\\\\\\implies x = \dfrac{25}2\\\\\\\implies x = 12 \dfrac 12\\\\\\\text{Hence 9 is}~ 12\dfrac 12\% ~ \text{of}~ 72

4 0
2 years ago
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shepuryov [24]

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sqrt(21)

Step-by-step explanation:

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