Question

I need help with quadratic functions :( anyone

Answer 1

Okay. Do you need the formula?

Answer 2

isnt it ax=bx+c?

Answer 3

No a quadratic equation has the form ax² +bx +c = 0

Answer 4

The formula is a little more complex. Do you need it?

Answer 5

yea sure

Answer 6

i just need help graphing though and finding the x and y intecept

Answer 7

Okay the x intercepts (almost always it has 2 x intercepts) are the answers.

Answer 8

For example for the quadratic equation 2x² +4x -30 =0
x = 3 and x=-5

Answer 9

well can you help me with this problem? please

Answer 10

Sure - post the problem.

Answer 11

ok one sec

Answer 12

f(x)=x^2+6x+2

Answer 13

Here's the formula:

Answer 14

ohh yeah i know that formula thats the quadratic formula

Answer 15

In the equation a=1 b=6 and c =2
putting these into the formula:
x = -6 +-sqroot(36 -4*1*2) / 2*1 =
-6 +-sqroot(36 -8) / 2
x = -6 +-sqroot(28) / 2
x = -6 +-5.2915 /2
x = -6 +2.64575 = -3.35425

x= -6 -5.2915/2
x= -8.64575

Answer 16

so whats the x and y intercept and how do i graph it

Answer 17

That has a few mistakes
x = -6 +-5.2915 /2 means the 6 AND the 5.2915 get divided by 2

x = (-6 +5.2915) /2
x= -0.7085 /2
x = -0.35425

x = (-6 -5.2915) /2
x = -11.2915 / 2
x = -5.64575

Answer 18

The CORRECTED x intercepts are directly above
x = -0.35425
and x = -5.64575

Answer 19

The y intercept occurs when x =0
f(x)=x^2+6x+2

f(x) = 0 + 0 +2
y intercept = 2

Answer 20

my math teacher did the first one

f(x)=x^2+4x-5
-b/2a=-4/2(1)=4(-2)-5=9
vertex(:-2,-9)
y-intercept=f(0)=0^2+4(0)
x-intercept=0=x^2+4x-5
x+5=0(subtract 5 from both sides) you get -5
x-1=0(add 1 to both sides) you get 1
so the x intercepts are (-5,0) and (1,0)

Answer 21

Why did you put up a new equation for that one?

Answer 22

The equation you first gave me was
f(x)=x^2+6x+2
then you posted
f(x)=x^2+4x-5

Which equation do you want to work on?

Answer 23

because she said when your looking for the vertex you use -b/2a which comes from the quadratic formula

Answer 24

ohh the one i gave you before i was just showing you what my math teacher said

Answer 25

So, we should have strted with the already worked out equation f(x)=x^2+4x-5 ?

Answer 26

ok thats fine we can do that but shes already did that one so im trying to do the rest

Answer 27

Okay going back to the original equation f(x)=x^2+6x+2
I have solved it.

Answer 28

ok so how do you graph it? if you dont mind drawing a graph

Answer 29

Do you have Excel on your computer?

Answer 30

no :(

Answer 31

so what do i do

Answer 32

I use Open Office and with it, I just made this:

Answer 33

wow i dont think i have that either

Answer 34

Well it is free. and you can download it here:
http://www.openoffice.org/download/

Answer 35

ok i will i have to go eat dinner

Answer 36

ok - hope I helped you out

Answer 37

yeah you did thank you :)

Answer 38

u r welcome