SOLUTION: Hello - need help PLEASE!! I need to determine if the given x-value is a zero of the function - show work f(x)=x^3+5x^2+2x-8 Is x= -2 a root -- don't undrstand at all thanks

Question 94022: Hello - need help PLEASE!!
I need to determine if the given x-value is a zero of the function - show work
f(x)=x^3+5x^2+2x-8
Is x= -2 a root -- don't undrstand at all
thanks
llo
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
f(x)=x^3+5x^2+2x-8
Is x= -2 a root
------------------
If -2 is a zero of the function f(-2) will be zero.
Try it:
f(-2) = (-2)^3 + 5(-2)^2 + 3(-2) -8
f(-2) = -8 +5*4 -6 -8
f(-2) = -22 +20
f(-2) -2
---------------
Since the result is not zero -2 is not a zero.
Cheers
Stan H.
RELATED QUESTIONS
need to determine if the given x-value is a zero of the function - show work f(x)=x^3 +... (answered by stanbon)

I need to determine if the given x-value is a zero of the function - show work... (answered by Nate)

Can someone help me with this? Thank you. I need to find all the zeros of the function... (answered by ikleyn)

Here is another one..I am stumped as to what to do!! Help please!! I need steps to... (answered by MathLover1)

will someone please help me? my question is: how do i find the the given X- value that... (answered by jim_thompson5910)

9. Use the intermediate value theorem to determine whether the polynomial function has a... (answered by Theo)

Hello! I need help solving this: I have the function:f(x) = 4x^3 + 5x^2 + 36x + 45... (answered by Fombitz)

Use synthetic division for the given polynomial f(x) = 2x3 -5x2- 4x + 3, find all the... (answered by venugopalramana)

I so badly need someones help asap. I have 6 problems i really need help with. Can... (answered by Alan3354)