Find the zeros for the function f(x) = 4x^3 - 9x^2 + 5

Question

anonymous · Answer

There are many ways you can find zeros. I suggest using a graph, unless you want to factor that out.

anonymous · Answer

I need to show work by algebraically finding it of factoring. Can you help with that

ikram002p · Answer

factoring is much easy to do it , first see factors of 5 which are 1.-1.5,-5,
and see which one can make the function zero will u try that plz ?

anonymous · Answer

I didn't know I could do that... I guess the only one that works is 1

anonymous · Answer

But there is also an irrational root around 1.9 (based on the graph)

ikram002p · Answer

ur correct only 1 work :)
i got f(1) =0
that make 1 is one zero so
(x-1) is a factor of   4x^3 - 9x^2 + 5
nw we use long divition

anonymous · Answer

I got 4x^2 - 5x + 5

ikram002p · Answer

nw lets continue
|dw:1406672376547:dw|

ikram002p · Answer

so
 4x^3 - 9x^2 + 5=(x-1)(4x^2-5x-5 )

so yes nwu have one zero which is 1
and use quadratic general formulla to find Zero's of 4x^2-5x-5

ikram002p · Answer

could u do that ?

anonymous · Answer

Did you mean this? |dw:1406672650106:dw|