Answer:

Step-by-step explanation:
Assuming this complete problem: "A cell tower is located at (-8, 4) and transmits a circular signal that covers three major cities. The three cities are located on the circle and have the following coordinates: G (-4, 7), H (-13, 4), and I (-8, -1). Find the equation of the circle"
For this case the generla equation for the circle is given by:

From the info we know that the tower is located at (-8, 4) so then h = -8 and k = 4, so then we need to find the radius. So we have the equation like this:
If the 3 points are on the circle then satisfy the equation. We can use the first point (-4,7) and if we replace we can find the value for 

So then 
And if we replace the second point we got this:

And for the third point we have:

And we got the same result.
So then our final equation is given:

Answer:
Step-by-step explanation:
4x+2y = -24 -------------(i)
<u> -4x+y = 12 -</u>------------(ii)
add (i) &(ii) 3y = -12
y = -12/3
y = -4
Put y = (-4) in (i)
4x + 2*(-4) = -24
4x - 8 = -24
4x = -24 + 8
4x = -16
x = -16/4
x = -4
Answer:
200
Step-by-step explanation:
2000 girls :1000 boys
2000 +1000 =3000
20% of 3000 = 600
I girl : 2 boys
1+2=3
600÷3 = 200
200 boys wore glasses
Answer:
the directrix and focus the axis of symmetry (goes through the focus, at right angles to the directrix) the vertex (where the parabola makes its sharpest turn) is halfway between the focus and directrix.
Step-by-step explanation: