"You do not eat bread."
Translation:Tu nu mănânci pâine.
"Tu nu mănânci pâine" = "You do not eat bread" (singular "you")
"Voi nu mâncați pâine" = "You do not eat bread" (plural "you")
"Dumneavoastră nu mâncați pâine" = "You do not eat bread" (very polite form, you need to find out from the context if it's the singular "you" or the plural "you")
i got a "correct" for that just now, so if you did not it has probably been included soon after yours or someone else's remark. But it is not a matter of formal&informal, or so it seems tu me, but tu is singular and voi is plural.