"Have you a red dress" is the same as "Do you have a red dress" yet it was marked wrong???
You are correct it is proper. However, here in America at least, "Have you a red dress" sounds a little stilted and not likely to be used in conversation.
Same here. In the UK we'd be unlikely to use the unnecessary 'got' The Spanish don't either, more to the point.
Can someone explain the difference between "rojo" & "roja" in this instance? Why can't "roja" be used?
el vestido is grammatically masculin so "el vestido rojo"
la camiseta is feminin so " la camiseta roja"
los zapatos are plural Masc., so " los zapatos rojos"
las fresas are plural Fem., so " las fresas rojas"