Finding x-intercept for a polynomial?? (1 Viewer)

[a1079atw]

Hi guys,

Please help me, I need to sketch f(x)=16+4x³-x⁴, I've found the stationary point and division point, but I don't know how to solve for x-intercept!
I tried to substitute the factors of 16 but none of them gives me y=0...

Thanks in advance!

 

[Carrotsticks]

From where did you get this question?

Although you are usually encouraged to try to find the x intercepts, some questions have messy (even impossible to find) values for its roots.

This is one of those, which is the reason I asked from where you got this question. Textbooks usually have relatively nice answers.

 

[a1079atw]

From where did you get this question?

Although you are usually encouraged to try to find the x intercepts, some questions have messy (even impossible to find) values for its roots.

This is one of those, which is the reason I asked from where you got this question. Textbooks usually have relatively nice answers.

I got it from my tutor. It is in the topic about geometrical application of derivative, and in the section about stationary point, maximum and minimum turning point.
Here's the actual question:

 

[Drongoski]

Question in terrible Ingrish!

 

[seanieg89]

If your tutor wrote that, get one who can write questions in proper English. It makes no difference here (you are not asked to and not expected to find roots), but in more difficult questions it can easily lead to confusion.

 

[a1079atw]

Question in terrible Ingrish!

Haha I know, but he's a good teacher