Why V- = 0 in Paint Doc Op-Amp Question

[Miike012]

Problem in paint doc.
I'm interested in why V_- = 0.

Is it always true that V_- = 0?
If not how was it decided that V_- = 0 for this given probem?

 

[Miike012]

Nevermind I figured it out. V₊ = 0
and V₊ = V_-

 

[rude man]

You still asked a good question. Is V- always zero?
Answer: no, but it's always = V+ unless the op amp output is saturated.