Find the parabola through (
−
7
,
−
39
)
(
-
7
,
-
39
)
with vertex
(
−
4
,
−
12
)

y = - 3x² - 24x - 60

Step-by-step explanation:

The equation of a parabola in vertex form is

y = a(x - h)² + k

where (h, k) are the coordinates of the vertex and a is a multiplier

Here (h, k) = (- 4, - 12 ), thus

y = a(x + 4)² - 12

To calculate a substitute (- 7, - 39) into the equation

- 39 = a(- 7 + 4)² - 12 ( add 12 to both sides )

- 27 = 9a ( divide both sides by 9 )

- 3 = a

y = - 3(x + 4)² - 12 ← in vertex form

Expand (x + 4)²

y = - 3(x² + 8x + 16) - 12

   = - 3x² - 24x - 48 - 12

y = - 3x² - 24x - 60 ← in standard form

   = - 3(x²

-3

step-by-step explanation:

a drawing really does here:

so i draw the horizontal line y=2 and the vertical line x=-2 at this intersection i put b (this is where my right angle is going to be).   so point b is at (-2,2).   point a is 5 units long and is also on y=2 so this point has to be (3,2) or (-7,2) -doesn't matter i will go with (3,2).

now we know c is at (-2,y) we don't know the y yet bet we know that c is on x=-2.

we have the area of the triangle is .5bh=12.5

we know the base length is 5 (ab)

we have the height is (2-y) if you look at your

plug in

.5(5)(2-y)=12.5

solve for y to get the y-coordinate for c

2.5(2-y)=12.5

divide both sides by 2.5 giving:

2-y=5

now subtract 2 on both sides

-y=3

y=-3

answer: c.  

step-by-step explanation:

mixtures containing substances that get attracted to magnet can be separated using a magnet. we can separate iron from a mixture of sand and iron, as only iron attracts to the magnet.