Question

how do i find out the vertex of a parabola knowing just this: y= -5x^2 ?

Answer 1

(0,0)

Answer 2

a = 5
b = 0
x = -b/a
x = 0
y = -5(0)^2
y = 0
(0,0)

Answer 3

I mean x = -b/(2a)

Answer 4

i’m sorry what
i didn’t understand that

Answer 5

Do you know there is a formula for the vertex of a parabola?

Answer 6

really?
what is it

Answer 7

http://www.algebra-class.com/vertex-formula.html
x = -b/(2a), where the equation is ax^2 + bx + c

Answer 8

i mean 2nd function

Answer 9

Have you learnt derivative?

Answer 10

no i haven’t

Answer 11

ok for this one, it's obvious that the vertex is at (0,0). For other quadratic equation, use complete the square

Answer 12

ok

Answer 13

can you just give me a step-by-step tutorial on how to find out the vertex? maybe if it has something to do with the mirror axis or w.e.

Answer 14

Or you mean the xavier method, right?

Answer 15

\[5x ^{2} = (5x)(x) \]

Answer 16

\[(5x)(x) = 0\]
x = 0

Answer 17

idk what xavier method is

Answer 18

just tell me verbally what i need to do plz.

Answer 19

First you find their x-intercepts
Then add them together, divided by 2. You get the axis of symmetry.
Plug the x value back to the original equation and you get y
Then, the vertex is (x, y)

Answer 20

thank you so much

Answer 21

you are a very nice person

Answer 22

wait but what do you mean “add Them” TOGETHER? what is tHEM???

Answer 23

ohh the 2 intercepts nvm sorry

Answer 24

but what if

Answer 25

it only has 1 intercept

Answer 26

how do i know if i should add it together

Answer 27

Then there's only 1 intercept.
For example for this one, zero + zero, then divided by 2
it's still zero

Answer 28

i know but..

Answer 29

look