Question

Y=-X^2+14X-49
Find the -X INTERCEPT and the coordinates of the vertex of the parabola

Answer 1

x intercept is the value of x when y = 0..so set y to zero then solve for x...the vertices i forgot @dpaInc may know though

Answer 2

for the vertice, get it in this form by completing the square:
4a(y-k) = (x-h)^2
where (h, k) is your vertex.

Answer 3

there's actually another way of getting the vertex but I can't recall it. it went something like b/2a ?... sound familiar?

Answer 4

nah

Answer 5

??

Answer 6

sounds like quadratic formula @dpaInc =))

Answer 7

The x-coordinate for the vertex of the parabola is
x=-b/2a

Answer 8

that's it....

Answer 9

And then plug in to solve for the y-coordinate.

Answer 10

where dhe go?

Answer 11

I think he got it. :D

Answer 12

factor and set equal to 0

--> -(x-7)^2 = 0

x = 7

Answer 13

also i think i have a formula for y coord of vertex from a, b, c

y = c - (b^2)/4a

Answer 14

it sounds like it's gonna be way easier if you just chug the value of the x-coordinate into the equation. :)

Answer 15

yeah lol

Answer 16

just threw that in there for the sake of it

Answer 17

but that's a good answer still..

Answer 18

Notice that \[y= -x^2+14x-49 =- (x^2 -14 x +49)=-(x-7)^2 \]
So the x-intercept is x=7 and the vertex is (-7,0)