Question

Find the Vertex:
f(x)= -3x^2-7x+6

Answer 1

@saifoo.khan helpppp lol

Answer 2

Hey.

To find vertex there's a shortcut.

Answer 3

uh huh

Answer 4

to find the x-cordinate, use this formula:

-b/2a

Answer 5

-(-7)/2(-3)

Answer 6

that will give me the vertex ?

Answer 7

Yes. "x-cordinate" of vertex.

Answer 8

Solve it first..

Answer 9

kk hold on :)

Answer 10

Holding.. :)

Answer 11

got 7/6

Answer 12

vertex is (h,k) right? so i believe that is the "h" ?

Answer 13

Perfect. ^

Answer 14

Find k now.

Answer 15

how to find k lol ?

Answer 16

Lol. Use GOogle. Jk.

Answer 17

i got it lmao :))

Answer 18

hold on

Answer 19

Okay. so now use 7/6 to find it.

y = -3x^2-7x+6
y = -3(7/6)^2 -7(7/6) + 6

solve.

Answer 20

got decimal :( hate decimal

Answer 21

so the vertex would be : (7/6, -6.24) ?

Answer 22

Should be 121/12

Answer 23

wtf ?

Answer 24

how? :O

Answer 25

-156/25

Answer 26

hey come back here >:o

Answer 27

VERTEX SHOULD BE -7/6. -_-

Answer 28

THE X-CORDINATE.

Answer 29

CALM DOWN !! CAPS WAR XD

Answer 30

ONE NEGATIVE SIGN RUINS EVERYTHING. >_<

Answer 31

so -7/6 because its opposite of 7/6 ?

Answer 32

you suppose to change it everytime ?

Answer 33

how come my teacher didn't change it -_____-

Answer 34

No. we calculated the x-cordinate wrong in the first place.

Answer 35

oh....XD

Answer 36

\[-\frac{b}{2a} \to -\frac{(-7)}{2(-3)}\to \frac{7}{-6} \to -\frac 76\]

Answer 37

ohhhhhhhhh i see now lmao hhahaha :D

Answer 38

omfg...my whole problem is wrong, thanks saif ! lol : XD

Answer 39

+99 medals

Answer 40

;D
Thanks.

Answer 41

hmm instead of 121/10 should i just leave it as 10.08 cuz i have to graph this afterward ?

Answer 42

great now i gotta calculate x-int and y-int :|
let see......

Answer 43

Sure.
Same thing. Depends on in what format your teacher wants

Answer 44

stay there.. lol

Answer 45

Lol. okays.

Answer 46

stuck lol....find x-intercept?

Answer 47

i know let y=0

Answer 48

0=-3x^2-7x+6

Answer 49

-6=-3x^2-7x <-----stuck here..

Answer 50

Use quadratic formula

Answer 51

oh yee

Answer 52

https://www.khanacademy.org/math/algebra/quadratics/quadratic_formula/v/quadratic-formula-1

Answer 53

but the way my teacher did it was to set y=0 and just add and divide stuff on left and right side...which is confusing but i suppose we can use quadratic aswell :)

Answer 54

Your teacher must have used the "completing the square" method. It's hella confusing. It confuses me too. :/

Answer 55

yeah thats what that was, completing the square lol....
ok i got y= 7+- sqrt(-23)/-6
and what's next ?

Answer 56

i dont think u can reduce it down or anything right? and u can't even square root a negative

Answer 57

https://www.khanacademy.org/math/algebra/quadratics/quadratic_formula/v/quadratic-formula-1

Answer 58

No. We can't reduce.

Answer 59

u can't even square root a negative
Yes you're very right.

Answer 60

ohh i get it, it's 7+- 23i/-6

Answer 61

Roots are: -14 and 0.

Answer 62

Roots are: -3 and 2/3

Answer 63

what? @_@

Answer 64

was that you on the video? https://www.khanacademy.org/math/algebra/quadratics/quadratic_formula/v/quadratic-formula-1

Answer 65

Haha. Ofcourse not.