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