Question

Find the x-intercepts of the parabola with vertex (-4,2)and y Intercept (0,-30) Wright answer if this form (x1,y1)(x2,y2).

Answer 1

i would also like to know how you did it

Answer 2

what's the vertex form of the parabola ?

Answer 3

(y-k)=a(x-h)^2

Answer 4

Bruh...

okay here: http://openstudy.com/study#/updates/4fe123c7e4b06e92b8705343

Answer 5

hmm add k both sides so it would be \[\huge\rm y=a(x-h)^2+k\] vertex form
where (h,k) is the vertex
so substitute (h,k) for ( -4,2)

Answer 6

so like (y-2)=a(x--4)^2

Answer 7

ye that would work
so y-intercept is (0,-30) where x =0 and y =-30 so plugin \[\huge\rm -30-2=a(0-(-4))^2\] now solve for a

Answer 8

so a =-2

Answer 9

i appreciate your help btw

Answer 10

yes right now u can find x-intercept \[\huge \rm -30-2=-2(x-(-4))^2\]
solve for x
let me know if you don't know how to work it out

Answer 11

x= 0,-8 Correct?

Answer 12

hmm plz show a little work...

Answer 13

im using an online calculator because the only calculator we have broke im not quite shure how to do the steps myself without it.

Answer 14

hmm well do you want to know how to work it out without calculator ?

Answer 15

couldent hurt mind if i get my notepad and pencil

Answer 16

ok i got it

Answer 17

alright first we can multiply negative by (-4)
-1 times -4 = 4 ( negative times negative = positive )
\[\huge \rm -30-2=-2(x+4))^2\]
-30-2 = -32
\[\huge \rm -32=-2(x+4)^2\]

now we should foil (x+4)^2

`(x+4)^2 `is same as (x+4)(x+4)

Answer 18

now we should distribute 2nd parentheses by first and 2nd term of the 2nd parentheses (foil method )
so multiply left first term by top