In responding to the question:"Is there absolute truth in this
world?", explain why positive, negative, and even agnostic answer
might still carries or implies an absolute idea?

Hi! First the answer: yes, there ia absolute truth.
Now the explanation (in my words):
1 The truth is a statement or condition or situation that is in
accordance with the reality.
2 Absolute is an adjective that can be ascribed if the commented
carachteristic can stand or exist without comparition with something
else. Following that, 'relative' does not mean less good or less
important but that a certain caracteristic can only be judged when
compared with something else.

All the things are by their nature either absolute OR relative. The
Greek philosophers didn't realize this and were greatly mislead. Not
only that, but they passed on their misconceptions to us in the form
of agnosticism or a negative attitude toward cognition of the absolute
truth.
Let me explain: Is this orange sour or sweet? Well... that depends on
my taste, doesn't it? But when asked how many oranges are on the
table, everybody will say the same answer. Do you agree? I guess you
may even wonder how can someone NOT to agree? :) But they do!! Oh,
they do! Listen to their (simplyfied) reasoning:

"You enter a room. There's a brown square desk in front of you. The
sun reflects against its polished smooth surface right in its center.
Get the picture? Now you squat and move one meter to the right. The
table has changed its appearance: now it is more prolonged in the
perspective. The reflection is not in its center. And if you look the
surface under the microscope, you'll see it is not smooth at all....."
or...
"How long is Dalmatian coast? Noone can tell! If you measure it
travelling with the boat, you will get one result. If you follow the
goat-trails all along the coast, the answer will increase. It will
increase even more if you count all the rocks and caves... And if you
use the microscope and include all the little holes on the rocks, what
result will you get? Of course, we can include the spaces between the
atoms on the molecular level! All the answers are facts and valid. Why
would one answer be reckognized and other not just because it is not
so usual?"

 They conclude we are fooled by our senses. And than extend it to: It
all depends! Nothing is for sure! There's no black and white!....
Sounds familiar? :) 

Yes, such reasoning is soooo common. It provides an easy way out. A
quick switch to turn off the conscious and responsibility. On a
"scientific" basis! :)
And that's why the agnostic and negative attitude toward the existence
of the absolute truth still exists.

When in matter of facts ALL things ARE EITHER relative OR absolute.
Even the abstract terms: if there were not a single man, would 2+2
still be 4? See - mathematics has an absolute caracter. Proportions
would still exist even if there is nobody who can count. But what
about the music? Since the sense of music is only created in the human
minds, without them it doesn't stand alone. Its existance is in
relation/relative to the human existence.

So there ARE both relative and absolute truths. It's a fact - there's
no arguing abut it. One can only choose to ignore it and "be kind to
oneself" (Mt 16:22)

If you think about it, you'll come to realize that CREATED things have
a relative caracter to them; Ask yourself: if a given object is the
only object in the universe, would you still be able to judge it?
Would you still be able to say it's sweet or big or heavy or whatever
when having nothing to compare it with?
The answer is a definite no. Even Jesus, when adressed as 'good' -
obviosly in an absolute sense - rejected that adjective as
inappropriate and said: "Why do you call me good? Nobody is good,
except one, God." Mark 10:18

There is only one person in the universe whose love, power, wisdom,
justice etc will still be full and intact even if there is nothing
else in existence but him - the almighty creator Jehovah God. The
creator doesn't depend on his creations, but vice versa.
And that brings us to the ultimate answer:
"Every good gift and every perfect present is from above, for it comes
down from the Father(...)" James 1:17 So is His Word, the Bible.
And that's why Jesus rightfully answered your question: "Your Word is
THE truth" John 17:17

I don't think that fruitfly-ga's comments are very helpful.
The Greeks certainly did have a concept of relativism. Protagoras of
Samos was famous for saying that 'Man is the measure of all things'.
And Plato argued against this protagorean relativism in his dialogues
'Protagoras' and 'Theaetus' [150ff.] His refutation of Protagoras in
the Theaetetus is masterly.
And the agnosticism reference is nothing to do with God. Rather, it is
about whether we can know for certain whether there are absolute
standards of truth or not.

I don't care to do your homework for you but here are some hints.

You could usefully consider several theories of truth, e.g. the
Correspondance theory, the Coherence theory and the Pragmatic theory.

You could then try arguing that even the most relativistic or
subjective interpretation of truth has a necessary back-reference to
absolute standards of truth. So, if I say 'It feels cold to me,
therefore it is cold for me' this might be due to the fact that I have
thin blood or am inadequately clothed.  But there are absolute
standards of what is warm or cold for human beings and these can be
objectively measured with a thermometer.