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:
1600 integers
Step-by-step explanation:
Since we have a four digit number, there are four digit placements.
For the first digit, since there can either be a 5 or an 8, we have the arrangement as ²P₁ = 2 ways.
For the second digit, we have ten numbers to choose from, so we have ¹⁰P₁ = 10.
For the third digit, since it neither be a 5 or an 8, we have two less digit from the total of ten digits which is 10 - 2 = 8. So, the number of ways of arranging that is ⁸P₁ = 8.
For the last digit, we have ten numbers to choose from, so we have ¹⁰P₁ = 10.
So, the number of integers that can be formed are 2 × 10 × 8 × 10 = 20 × 80 = 1600 integers
Answer:
36 meters^3
Step-by-step explanation:
Formula: Bh
B=Base area
h=height
to find the base area, multiply 2 and 6
2x6 = 12
B=12
and the height is given, so just insert your numbers into the formula
12x3=36
There are 15 articles of clothing
5 are blue and 10 are red
5/15 will give you a percent which is your answer
Answer 0.333333333
13=10+3 so
13-7=3+10-7=3+3=6
