I have heard many students saying "I am agree with you" or "I am not agree with you". This is completely incorrect. The correct versions are:
1. I agree with you.
2. I disagree with you (your point).
3. I am in agreement with you.
4. I am in disaagreement with you.
point#3,4 are very formal. point#1,2 are frequently used, correct versions to express agreement r disagreement withothers.
Happy learning,
Anshu Nadir