Question

Kelsey has a list of possible functions. Pick one of the g(x) functions below and then describe to Kelsey the key features of g(x), including the end behavior, y-intercept, and zeros.
g(x) = x3 − x2 − 4x + 4
g(x) = x3 + 2x2 − 9x − 18
g(x) = x3 − 3x2 − 4x + 12
g(x) = x3 + 2x2 − 25x − 50
g(x) = 2x3 + 14x2 − 2x − 14

Create a graph of the polynomial function you selected from Question 2.

Answer 1

You know that cubic functions always have 3 x-intercepts

Answer 2

uhm yes

Answer 3

im really bad at this

Answer 4

If you let y=0, you can find the x intercepts, and if you let x=0, you can find the y-intercepts. It involves factoring

Answer 5

first of all; pick an equation.

Answer 6

ok um lets do g(x) = x3 + 2x2 − 9x − 18

Answer 7

okay. now personally; I would go and use an online graphing calculator like www.desmos.com

Answer 8

but if you cant do that then you want to factor it.

Answer 9

Yes! I like desmos

Answer 10

okay, then go to desmos to find your x and y intercept

Answer 11

ok let me try real quick

Answer 12

IF you cant use that, then you would factor your equation, and find the x intercepts

Answer 13

ok could you walk me through that?

Answer 14

Using demos is a little cheaty lol

Answer 15

eh. it gets you the answer. and if you teacher is giving you open book then id say go for it

Answer 16

It's still good to know how to factor cubic fuctions though :P

Answer 17

I got x ints at -2 -3 and 3

and yes it is. Im happy to help her factor if that is her problem though

Answer 18

and y int at -18 :)

Answer 19

Thankyou! However I typed in the function I picked and it said it didn't understnd it? lol

Answer 20

Oh thats because I put (g)x not (f)x

Answer 21

you cant use copy and paste on that. just type it out :P if you type out g(x) it works as well

Answer 22

oh thats weird haha

Answer 23

So I have my y int description as -18

Answer 24

yes