Rational functions: domain of Fx=-2(x^2-4)/3(x^2+4x+4)

[fefe1507]

I need help finding the domain of a rational function. Fx=-2(x^2-4)/3(x^2+4x+4) i know you have to solve the deomnator for zero but i cant get it to come out right

 

[Deleted member 4993]

Re: Rational functions

I need help finding the domain of a rational function. Fx=-2(x^2-4)/3(x^2+4x+4) i know you have to solve the deomnator for zero but i cant get it to come out right

What do you mean when you say "i cant get it to come out right"?

Does it mean you tried to solve it - and the answer you get does not match the answer given in the book?

If so please show your work - we could catch your mistake and show you how to correct it.

 

[fefe1507]

Re: Rational functions

i set the bottom equal to 0
3(x^2 + 4x + 4 ) = 0
3 = 0 and x^2 + 4x +4 = 0
3 = 0 and (x + 2) = 0 and (x + 2) = 0
3 = 0 and x = -2 and x = -2

 

[Loren]

Re: Rational functions

If I understand correctly, you have come up with 3=0 (which it doesn't), or x=-2. If x=-2, then the denominator is zero. What does that tell you?

 

[Denis]

Re: Rational functions

i set the bottom equal to 0
3(x^2 + 4x + 4 ) = 0
3 = 0 and x^2 + 4x +4 = 0

You're not handling the "3" properly; look at it as (divide both sides by 3) :
x^2 + 4x + 4 = 0 / 3 ; so:
x^2 + 4x + 4 = 0 : kapish?