[Rookie]

I am told that there are 3.0 mL of 0.1 M of AgNO3 and 3.0 mL of 1 M NH3... and they're asking me to find the concentration of Ag(NH₃)₂²⁺
So, first i wrote a balanced reaction:
Ag(NH3)₂ --> 2NH₃ + Ag

Then i figured that it goes by stoichiometry so i took Ag+ and wrote:

0.003L * (0.1 mol Ag / 1L Ag) + (1 mol Ag(NH3)₂/ 1 mol Ag)
But, now what? and am i actually doing this right?

[lemonoman]

I am told that there are 3.0 mL of 0.1 M of AgNO3 and 3.0 mL of 1 M NH3... and they're asking me to find the concentration of Ag(NH₃)₂²⁺
So, first i wrote a balanced reaction:
Ag(NH3)₂ --> 2NH₃ + Ag

Then i figured that it goes by stoichiometry so i took Ag+ and wrote:

0.003L * (0.1 mol Ag / 1L Ag) + (1 mol Ag(NH3)₂/ 1 mol Ag)
But, now what? and am i actually doing this right?

Something's wrong with your question.

You talk about AgNO₃ mixed with NH₃, and they ask for Ag(NH₃)₂²⁺ ?   Are you sure?

[Borek]

Assuming ²⁺ is just a typo - this is either simple stoichiometry question (you assume all Ag⁺ reacted) or equilibrium question (you need to find complex formation constant). In the latter case something lice ICE table could be helpfull.