It's more problematic because English construction "going to", which is used to express future events, is quite often translated into Polish as the verb "zamierzać" used in present tense, although not always.
But "czy będziesz to jadł?" is translated as "are you going to it this?"
I fail to see any difference between the two sentences.
I'm not certain, I am not English native speaker. Maybe someone else could explain whether there is any difference between:. "You will have a new computer" and "You are going to have a new computer" and compare it to your sentence. Maybe there are some nuances.
It doesn't clear up much. In Polish "Czy zamierzasz to jeść?" would mean something like "Are you you really sure that you are going to eat it?" so I would rather say "Czy będziesz to jeść?" if I want to simply ask. "Czy zamierzasz (or better: "planujesz") mieć nowy komputer?" would mean "Do you plan to have a new computer?". Would you use "going to" then?
As hughcparker wrote in another comment, that's not how you say that in English. The form "be having" is only used in special cases.
It's OK, but only if you speak with an Irish accent - see my earlier response to hughcparker's comment for more.
My Polish A1 book (hurra po polsku) says that you shouldn't use the infinitive form of mieć with będXXX, but only the past form. I don't know how hard rule it is, but it is important enough to remark it.
They are both correct and used in written and spoken Polish. I think the infinitive form was considered wrong in the past, but now it is legit :) The construction with infinitive is more simple, as it is gender neutral. Maybe your book forces you to use the past form of a verb, so you can learn genders better?
Rules of Polish language state* that you can't use infinitive with modal verbs, so „będziesz móc mieć”, doesn't exist and in such case the only option is past tense form, so either „będziesz mogła mieć” or „będziesz mógł mieć”(ie. we avoid double infinitive).
Other than that, both forms are equally valid. The infinitive form is actually older and comes from Proto-Slavic and in many Slavic languages is the only option for future tense; the to be + past form is a later Polish innovation(and I think it also spread to Kashubian, but I'm not sure).
* – At least according to poradnia PWN.
Oh, I didn't understand you. The Duo sentence "Będziesz miała nowy komputer" does not use "będziesz mogła mieć", so I just referred to the forms: "będziesz miała" or "będziesz mieć" - and they are both correct. Obviously you're right that "będziesz móc mieć" does not exist.
That just isn't how it would be said in English. At least, not in any variety I've encountered. You could say "you will be getting", if you were talking about being given a computer. I think this sentence is about owning a computer, though.
I'm fairly sure I've heard Irish English speakers use the rare Future Continuous form "You'll be having a..." to mean "You will own a...". Without the Irish accent it sounds rather quaint, however, so most learners of English as a foreign language will prefer to avoid it.
If feminine "miała" is used, does this mean that one is talking to a girl?