Spanish language Q&A Forum

Are por qué no/ mejor no only used with vamos? Or are these phrases more commonly used for all commands (not just ir)? 

For the road signs, are they third person singular for affirmative commands, and third person plural for negative commands? Or are both singular and plural third person used equally for either negative or affirmative commands?

Just want to mention that there are a few spacing errors that make identifiers show up in the wrong place.  Ex:  Ella no quiere que nosotros comamos tan rápido. (present subjunctive)

She doesn't want us to eat so fast.

I have a question regarding the following excerpt:

"Both "¿Por qué no...?" and "Mejor no..." followed by El Presente are more frequently used in speech than their equivalent forms using the imperative:

Vayamos a la playa.
Let's go to the beach! (affirmative command)

No vayamos a la playa.
Let's not go to the beach! (negative command)"

My understanding is that whilst 'vayamos' is the negative imperative form of 'ir', 'vamos' is the affirmative form, contrary to the above.

Is there a situation where we would use the subjunctive 'vayamos a la playa' instead of the affirmative imperative 'vamos a la playa' to express the same command?

Many thanks,

Stu

I guess I wasn't clear in my question.  The "any" in parens is what I added in my question.  There were no parens in the English in the lesson.

Also I was asking if "No hagan ningún ruido" is the correct way to say "Don't make any noise."     

Maybe it's just me, but I find it very difficult when translations are so different from each other.  Quite often the subleties escape me.

Just wondering why the extra word is in the English translation.

No hagan ruido
Don't make (any) noise    Kwiziq

No hagan ningún ruido 
Don't make any noise     

Does “Vámanos” fit in here?  I have heard it used but don’t really understand the reasoning behind it.  Is it another informal command for “Let’s go” to ourselves, like “Vamos”,  or is it from the verb “Irse”?                      Sorry, I know it is not part of this lesson you are teaching but I have been curious about it.  

I know that "no vayamos" is the correct negative command for "ir"; but I was under the impression, and my Barron's verb book confirms, that the correct affirmative imperative for "ir" is "vamos" not "vayamos".