Question

can anyone help me with quadratics??

Answer 1

what's your question?

Answer 2

Derive the equation of the parabola with a focus at (4, −7) and a directrix of y = −15. Put the equation in standard form.

Answer 3

f(x) = one sixteenthx2 − 8x + 11
f(x) = one sixteenthx2 − 8x − 10
f(x) = one sixteenthx2 − one halfx + 11
f(x) = one sixteenthx2 − one halfx − 10

Answer 4

first step is to set up the distance formula

Answer 5

then we set the distance from the diretrix on the other side

Answer 6

so now simplify

Answer 7

square both sides

Answer 8

k

Answer 9

3.8

Answer 10

where is that 3.8 coming from

Answer 11

lol i sqared 15

Answer 12

are you familiar with binomial expansion?

Answer 13

kinda alittle bite @Vocaloid

Answer 14

good, so how would you expand

(x-4)^2?

Answer 15

x2−8x+16

Answer 16

good, what about

(y+7)^2?

Answer 17

y2+14y+49

Answer 18

good, now what about (y+15)^2?

Answer 19

y2+30y+225

Answer 20

good now let's put that all together and solve for y

Answer 21

right off the bat we can cross out y^2

Answer 22

k so are going to combine like terms

Answer 23

yes

Answer 24

16 + 49 = 65 so

Answer 25

225 - 65 = 160 so

Answer 26

30y - 14y = 16y

Answer 27

know where to go from there?

Answer 28

nooooo

Answer 29

now we just re-arrange for y