Sałatka z dwóch warzyw jest szybka i zdrowa.

• In isolation, dwa is the nominative form meaning “two.”
• Here, the preposition z in the sense “from/made of” requires the genitive case.
• The genitive of dwa is dwóch.
• After a preposition that takes genitive, both the numeral and the noun must be in genitive: hence z dwóch warzyw.

• Warzywo is a neuter noun meaning “vegetable.”
• Its nominative plural is warzywa, but the genitive plural is warzyw.
• Because z (in the “from/composed of” sense) demands genitive, we say z dwóch warzyw.

• The preposition z has two main functions in Polish:
– Instrumental (“with/accompanied by”), e.g. z przyjacielem (“with a friend”).
– Genitive (“from/made of/origin”), e.g. z węgla (“from coal”).
• In sałatka z dwóch warzyw, z means “made of” or “composed of,” so it takes the genitive.

• Sałatka is a feminine noun.
• Adjectives in Polish agree with the noun they modify in gender, number, and case.
• In the nominative singular feminine, szybki → szybka and zdrowy → zdrowa.

No. In Polish, you generally do not place a comma before the coordinating conjunction i.
Example: szybka i zdrowa (no comma).

• In informal or advertising style you can drop jest and use a dash:
Sałatka z dwóch warzyw – szybka i zdrowa!
• In standard, full sentences, keep jest to form the predicate:
Sałatka z dwóch warzyw jest szybka i zdrowa.

Yes. Polish has flexible word order.
Putting szybka i zdrowa first shifts the emphasis to those qualities, but the sentence remains correct.

• Z dwoma warzywami uses the instrumental case and means “together with two vegetables.”
• To express composition (“made of two vegetables”) you need the genitive: z dwóch warzyw.

A simplified guide:
• Sałatka – “sah-WAHT-kah” (ł = English w, ą = nasal “on”)
• z – “z”
• dwóch – “DVOOKH” (ó = u, ch = as in Scottish “loch”)
• warzyw – “vah-ZHIV” (rz/ż = “zh” as in “measure,” final w = “f”)