1. The problem statement, all variables and given/known data
Thank you for the link Borek but i'm still lost
You have to directly apply the ICE table method to your case.
What is your HA? A-?
Basically it is about stoichiometry - from the dissociation reaction you can easily see that for each mole/molecule of A- (H+) produced, one mole/molecule of HA is consumed. You just have to express concentrations of all three substances involved (HA, H+, A-) in terms of one unknown - best approach is to use H+ as the unknown, as you are asked about pH.
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