Question

Need some help finding x intercepts algebraically

Answer 1

The example equation is
\[x^3+2x^2-4x-8\]

Answer 2

factor it

Answer 3

I can only factor parts of it right?

Answer 4

So \[x^3+2(x^2-2x-4)\]

Answer 5

\(\large\color{black}{ x^3+2x^2-4x-8=0 }\)
(setting the function equal to zero, so that we find the y-intercepts, right?)

\(\large\color{black}{ x(x^2)+2(x^2)-x(4)-2(4)=0 }\)

Answer 6

so you see how it can be tackled?

Answer 7

\(\large\color{black}{ x(x^2)+2(x^2)-x(4)-2(4)=0 }\)

\(\large\color{black}{ x^2(x+2)-4(x+2)=0 }\)

Answer 8

x intercepts but yes

Answer 9

yes, X intercepts, I meant that :)

Answer 10

So, you can finish it, right?

Answer 11

Oh! wow. Duh, thanks!

Answer 12

Alrighty :) You welcome!

Answer 13

Would it only be 2?

Answer 14

or since 4 is negitave

Answer 15

2 is one of the answers, but it is not the only answer.

Going from, \(\large\color{black}{ x^2(x+2)-4(x+2)=0 }\)

Answer 16

we get \(\large\color{black}{ (x^2-4)(x+2)=0 }\) (right ? )

Answer 17

So -2 and 2

Answer 18

yes!

Answer 19

With one condition though, that you get 2 twice.

Answer 20

I forgot what exactly it is called, but it is a repeating x-intercept.

Answer 21

So yes, 2 and -2.

Answer 22

Thanks a ton man

Answer 23

Enjoy !