Question

Did I get the right answer?
What is the equation of the quadratic graph with a focus of (5, 6) and a directrix of y = 2?
I got f(x)=1/8(x+5)^2+4

Answer 1

vertex shares the same x part ... so -5 is better just at a cursory view

Answer 2

+4 is fine since its the middle of 6 and 2

Answer 3

8 is fine, since 6-4 = 2 and 4-2 = 2 and 2*4 = 8

Answer 4

and the 1/8 looks fine with the 1/(4p)

Answer 5

Can you explain why the 5 turns into a negative? That confuses me :P

Answer 6

spose we have the function:

y = x^2

we can move this thing left or right by adjusting the value of the x part

y = (x+h)^2

the adjustment moves the x=0 to something else, x+h = 0 when x=-h

but a -x is not a convention that is used soo x-h gets played into action

Answer 7

spose we have a zero when x=5

(5+h) = 0 when h=-5

(x + (-5))

Answer 8

Okay so if the 5 were a negative, would it turn into a positive?

Answer 9

of course:

say we have a zero when x=-5

(-5+h) = 0 when h=5

(x+(+5))

Answer 10

Ohh okay, thank-you!

Answer 11

another view of it

x+h = 0 when h=-x

Answer 12

good luck :)