If they are parallel they will have the same slope , m
So in y = mx + c, if there are two equations which both have the same m value they will be parallel.
If the lines are perpendicular they'll have slopes like this: 1/2 to -2/1 - where they flip and a negative gets added.
In the equations: 10x + 5y = -5 , and y = -2x + 6
We can rearrange 10x + 5y = -5 to be in the form y = mx + c
10x + 5y = -5
5y = -5 - 10x
y = -1 - 2x
y = -2x - 1
Since y = -2x - 1 and y = -2x + 6 both have the same slope of -2 they are parallel!
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:
The answer would actually be 9,900
Answer:
#8 : x=15−y
#9: 
#10: y=2A−x
#7: T=
Step-by-step explanation:
Answer: 1.4
Step-by-step explanation:
To calculate the grade point average you have to sum all the points of each course multiplying the hours and then diveded by the total number of hours she did.
She earned a grade B in her 4 hour topology course, so she has 3*4 points.
In her 11 hour gouvernment course, she earned a grade D, so she has 1*11 points. In the 2 hour biology course she earned a grade D, so she has 1*2 points and in her 3 hours studio art course she had also a grade D, so she has 1*3 points
She has done 3+2+11+4 hours of subjects=20.
The total average is (3*4+1*11+1*2+1*3)/20=28/20=1.4
