Rational Functions

[sunwers]

I'm still having problems completing this problem. Here is a different question and it says I have completed it wrong. What am I doing wrong?

Step 1
Given the following rational function: f(x)=(x^2-9x-1)/(2x^2-4x-16)
Find equation for the vertical asymptotes, if any, for the rational function. Separate multiple equations with a comma.

when I factored 2x^2-4x-16 I got (2x+4)(x-4)
Set equal to 0
2x+4=0
2x=-4
x=-2

x-4=0
x=4

Answer to step 1 I got x=-2, x=4

Step 2
Find equations for the horizontal or oblique asymptotes, if any, for the rational function.
(x^2-9x-1)/(2x^2-4x-16)

y=(1x^2)/(2x^2)
y=(1)/(2)=1/2
y=1/2

Step 3
Enter four ordered pairs for the graph of the rational function.

I used x values except for Y=1/2, x=-2, x=4

f(-3)=((-3)^2-9(-3)-1)/(2(-3)^2-4(-3)-16)=(35)/(14)=5/2 (-3,5/2)
f(-1)=((-1)^2-9(-1)-1)/(2(-1)^2-4(-1)-16)=(9)/(-10)=-9/10 (-1/,-9/10)
f(0)=((0)^2-9(0)-1)/(2(0)^2-4(0)-16)=(-1)/(-16)=1/16 (0,1/16)
f(5)=((5)^2-9(5)-1)/(2(5)^2-4(5)-16)=(-21)/(-26)=21/26 (5,21/26)

It told me I got step 1 and 2 correct but step 3 was incorrect. Will someone please help me figure out what I'm doing wrong. I have worked on this for three days now and I get thru steps 1 and 2 but cannot get step 3 correct.

Thanks in advance for all your help

Sunwers

 

[JeffM]

I'm still having problems completing this problem. Here is a different question and it says I have completed it wrong. What am I doing wrong?

Given the following rational function: f(x)=(x^2-9x-1)/(2x^2-4x-16)

Enter four ordered pairs for the graph of the rational function.

I used x values except for Y=1/2, x=-2, x=4

((-3)^2-9(-3)-1)/(2(-3)^2-4(-3)-16)=(35)/(14)=5/2 (-3,5/2) Looks OK to me
((-1)^2-9(-1)-1)/(2(-1)^2-4(-1)-16)=(9)/(-10)=-9/10 (-1/,-9/10) So does this except for the slash after the - 1.
((0)^2-9(0)-1)/(2(0)^2-4(0)-16)=(-1)/(-16)=1/16 (0,1/16) Looks OK.
((5)^2-9(5)-1)/(2(5)^2-4(5)-16)=(-21)/(-26)=21/26 (5,21/26)

\(\displaystyle f(5) = \dfrac{5^2 - 9 * 5 - 1}{2 * 5^2 - 4 * 5 - 16} = \dfrac{25 - 45 - 1}{2 * 25 - 20 - 16} = \dfrac{-20 - 1}{50 -36} = \dfrac{-21}{14}.\)

It told me I got step 1 and 2 correct but step 3 was incorrect. Will someone please help me figure out what I'm doing wrong. I have worked on this for three days now and I get thru steps 1 and 2 but cannot get step 3 correct.

Thanks in advance for all your help

Sunwers

Looks like an arithmetic error to me.

 

[sunwers]

Looks like an arithmetic error to me.

Thank you JeffM,

I think I have been too long at trying to figure this out LOL. Need to take a break from Calculus. I forgot to square the 2(5)^2 so my answer should have been (5,-3/2). Thank you so much for your help. I was so happy to see my answer was correct after submitting it.