Using <u>complex numbers and radicals</u>, it is found that the correct option is C.
When a complex number is a root of a polynomial function, it's conjugate also has to be.
- Hence, since 8i is a root of the function, -8i is also a root.
The same is valid for radicals, as they are in the 
format.
- Since
is a root, 
is also a root.
Hence, option C is correct.
For more on <u>complex numbers and radicals</u>, you can check brainly.com/question/25173944
Answer:
Part A:
The surface area of a cylinder is given by
A= 6πr² if h= 2r
Part B:
Total Cost of covering the cylinder = Rate *2πrh + rate*2πr²
Cost of covering only the side = Rate *2πrh
Step-by-step explanation:
Part A:
The surface area of a cylinder is given by
A= 2πrh + 2πr²
Where h= height and radius = r
But we have the height twice as radius so h= 2r
So putting h= 2r we get
A= 2πr(2r) + 2πr²
A= 4πr² + 2πr²= 2πr²(2+1) = 2πr²(3)= 6πr²
Part B:
Cost = Rate * area of the wall + rate * area of the top and bottom
Cost = Rate *2πrh + rate*2πr²
Where area of the top and bottom= πr² +πr² =2 πr²
and area of the side = 2πrh
Multiplying both with the rate and then adding would give the total cost of materials needed to cover the outside of the cylinder and from top and bottom as well.
If you do not need to cover top and bottom then the expression would be
Cost of covering only the side = Rate *2πrh
Part C:
Already done above.
Answer:
She earned $20 in tips.
Step-by-step explanation:
First, you need to work out how much pay she'd get for 12 hours work:
12 x $11.25 = $135 for 12 hours work
Then, find out 2/5 of $11.25 to find out how much she would get for the 2/5 of an hour she worked:
2/5 of $11.25 = $4.50
Add both these sums together to get her total pay for hours worked:
$135 + $4.50 = $139.50
Subtract that sum from her total pay to find out how much money she earned in tips:
$159.50 - $139.50 = <u>$20</u>
12 times / 5 seconds * (60 seconds / 1 min) = 144 times / min
