Common rule here is adjectives modify nouns and adverbs modify verbs. However, some verbs may be modified by adjectives too. This is the list (not complete, basic required for GMAT) of such verbs: be, become, feel, get, look, seem, smell, sound.

Strictly speaking it should be:
I am doing well.
I am good.

Well is an adverb modifying "doing", Good is an adjective modifying "I".

If you switch the pronoun to 3rd person, it may be easier to see:

He is doing well.
He is good.

I don't agree with pemdas, adverbs cannot modify nouns/pronouns, and adjectives can only modify nouns/pronouns.
In those examples (be, become, feel, get...), if they are followed by an adjective, you have be sure it is modifying the noun/pronoun OR the verb.

for example:
He feels bad.
bad is an adj modifying "he" or the "state/condition" that "he" is in.

He feels badly.
badly is an adv modifying "feels", specifically "how" he feels

note the difference: one stresses/modifies the person and one stresses the action.

thank you, however did I say this?

capnx wrote:I don't agree with pemdas, adverbs cannot modify nouns/pronouns, and adjectives can only modify nouns/pronouns.

even reading post not sure ...

pemdas wrote:Common rule here is adjectives modify nouns and adverbs modify verbs. However, some verbs may be modified by adjectives too. This is the list (not complete, basic required for GMAT) of such verbs: be, become, feel, get, look, seem, smell, sound.

yes, the nouns can be modified as well as verbs - here's more primitive (may be) BUT practical example not repeating @capnx post
the trees grew long - the obvious part modified by adjective is tree BUT the adjective follows verb. It's not the order what matters - it's the modified part of clause which needs to be defined. I think this was the intention of previous poster?

I definitely did not say that adverbs cannot modify nouns

btw, i'm well & i'm doing well are two different meanings; one states physical condition and the other conveys general mood, state of affairs, etc.

Sorry I think u misunderstood. I'm saying adv cannot modify nouns/pronouns, and adj only modify nouns/pronouns.
and I'm disagreeing with your statement "some verbs may be modified by adjectives too."

thanks, BUT even with the corrected remark you are absolutely wrong. There is a certain type of verbs - 'sense verbs'. These verbs require adjectives NOT adverbs. I will not be typing what has already been typed for GMAT aspirants by 800 score
here's link https://www.800score.com/content/guidec4view1V2c.html

capnx wrote:Sorry I think u misunderstood. I'm saying adv cannot modify nouns/pronouns, and adj only modify nouns/pronouns.
and I'm disagreeing with your statement "some verbs may be modified by adjectives too."

I'm not an expert, BUT I think the click to your question is understanding the difference between action verbs and linking verbs. Likewise in the previous post - trees grew long - the modified part in essence was 'trees' BUT grammatically adjective does modify the verb "to grow" which is linking verb here, expresses a state of being not action. To save space/allow for our learning rules, I am attaching link https://www.englishcorner.vacau.com/gram ... kvrbs.html

catseye wrote:I have confusion about the two sentences:

I am well.
I am good.

Which one is correct? Why is one of them wrong?

Would any expert explain?

Thanks.

thanks for the link. I stand corrected

The main difference between well and good is that good is always used as an adjective. No exceptions to this.

Well can be used as an adjective as well as, as an adverb.

I am good---correct. good as an adjective defines I
I am doing well---correct. wellas an adverb is used for verb 'doing'.
I am well.---correct. Well is used as an adjective here.