Answer:
11.1803398875
Step-by-step explanation:
I will explain you and pair two of the equations as an example to you. Then, you must pair the others.
1) Two circles are concentric if they have the same center and different radii.
2) The equation of a circle with center xc, yc, and radius r is:
(x - xc)^2 + (y - yc)^2 = r^2.
So, if you have that equation you can inmediately tell the coordinates of the center and the radius of the circle.
3) You can transform the equations given in your picture to the form (x -xc)^2 + (y -yc)^2 = r2 by completing squares.
Example:
Equation: 3x^2 + 3y^2 + 12x - 6y - 21 = 0
rearrange: 3x^2 + 12x + 3y^2 - 6y = 21
extract common factor 3: 3 (x^2 + 4x) + 3(y^2 -2y) = 3*7
=> (x^2 + 4x) + (y^2 - 2y) = 7
complete squares: (x + 2)^2 - 4 + (y - 1)^2 - 1 = 7
=> (x + 2)^2 + (y - 1)^2 = 12 => center = (-2,1), r = √12.
equation: 4x^2 + 4y^2 + 16x - 8y - 308 = 0
rearrange: 4x^2 + 16x + 4y^2 - 8y = 308
common factor 4: 4 (x^2 + 4x) + 4(y^2 -8y) = 4*77
=> (x^2 + 4x) + (y^2 - 2y) = 77
complete squares: (x + 2)^2 - 4 + (y - 1)^2 - 1 = 77
=> (x + 2)^2 + (y - 1)^2 = 82 => center = (-2,1), r = √82
Therefore, you conclude that these two circumferences have the same center and differet r, so they are concentric.
Answer:
B) 5 x 4 x 3 x 2 x 1
Step-by-step explanation:
When you see a ! directly next to a number (such as 5!), it means that you are multiplying starting from that number, and stepping down each time:
5! = 5 * 4 * 3 * 2 * 1
For example, take factoral 10: 10!
10! = 10 * 9 * 8 * 7 * 6 * 5 * 4 * 3 * 2 * 1 = 3,628,800
In this case, you are multiplying 5!.
5! = 5 * 4 * 3 * 2 * 1 = (20) * (6) * 1 = 120
5! = 120
Step-by-step explanation:
<u>1</u><u> </u>*9^2 + 4
3
<u>1</u><u> </u>* 81 + 4
3
<u>1</u><u> </u>* 85
3
<u>85</u>
3
=28
Answer:
-15
Step-by-step explanation:
the new temperature since it went down
-12-3= -15
