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:
![67.5\text{ [square units]}](https://tex.z-dn.net/?f=67.5%5Ctext%7B%20%5Bsquare%20units%5D%7D)
Step-by-step explanation:
The composite figure consists of one rectangle and two triangles. We can add up the area of these individual shapes to find the total area of the irregular figure.
<u>Formulas</u>:
- Area of rectangle with base
and height 
: 
- Area of triangle with base and height :
By definition, the base and height must intersect at a 90 degree angle.
The rectangle has a base of 10 and a height of 5. Therefore, its area is 
.
The smaller triangle to the left of the rectangle has a base of 2 and a height of 5. Therefore, its area is 
.
Finally, the larger triangle on top of the rectangle has a base of 5 and a height of 5. Therefore, its area is 
.
Thus, the area of the total irregular figure is:
![50+5+12.5=\boxed{67.5\text{ [square units]}}](https://tex.z-dn.net/?f=50%2B5%2B12.5%3D%5Cboxed%7B67.5%5Ctext%7B%20%5Bsquare%20units%5D%7D%7D)
Answer:
Length: 5 ft; width: 4 ft.
Step-by-step explanation:
A = LW formula for area of rectangle
(2x + 1)(2x) = 20 substitute length, width, and area into formula
4x² + 2x - 20 = 0 use the distributive property to multiply out left side
2x² + x - 10 = 0 divide both sides of equation by 2
(2x + 5)(x - 2) = 0 factor out trinomial
2x + 5 = 0 or x - 2 = 0 use zero product rule to solve for x
2x = -5 or x = 2 subtract 5 from both sides; add 2 to both sides
x = -5/2 or x = 2
We discard x = -5/2 since it would give negative length and width, and the length and width cannot be negative.
Length: 2x + 1 = 2(2) + 1 = 5
Width: 2x = 2(2) = 4
Length: 5 ft; width: 4 ft.
Answer:
The answer is D i guess . ( Not completely sure )
Answer:
-1/14
Step-by-step explanation:
