This is a positive parabola so it opens upwards. The equation for the directrix of this parabola is y = k - p. k is the second number in the vertex of the parabola which is (0, 0), but we need to solve for p.

The form that the parabola is currently in is

$y=a(x-h)^2+k$ so that means that $a=\frac{1}{8}$ . We can use that to solve for p in the formula

$p=\frac{1}{4a}$ so

$p=\frac{1}{4(\frac{1}{8}) }$ which simplifies to

$p=\frac{1}{\frac{1}{2} }$ which gives us that

p = 2. Now to find the directrix:

y = k - p becomes

y = 0 - 2 so

y = -2, choice A.

6 0

3 years ago

A bag contains 21 red marbles, 4 white marbles, and 3 gray marbles. Do you randomly pick out a marble recorded color and put it

Svetach [21]

Answer:

Step-by-step explanation:

you add 21, 4, and 3 to find the total

then you find how many are white or gray

7/28= 1/3

1/3 times 84

84 times 1 divided by 3

84/3

5 0

3 years ago

X + y = 0 , x - y = -16 . what's x and what's y? (coordinates)

Darina [25.2K]

X + y = 0
x = - y

x- y = -16
y = x + 16

4 0

3 years ago