-solves for the variable-
(DEX + x)*3.4 + STR = (DEX*3.4 + STR)*(ATK + 2)/ATK
(DEX + x) = ((DEX * 3.4 + STR)*(ATK + 2)/ATK - STR) / 3.4
x = (DEX + STR / 3.4)*(1 + 2/ATK) - STR / 3.4 - DEX
= (DEX + STR / 3.4)/ATK * 2
Or the above. lol
Oh. And technically speaking that's only maximum damage, though it won't make a huge difference.
(DEX + x)*3.4 + STR = (DEX*3.4 + STR)*(ATK + 2)/ATK
(DEX + x) = ((DEX * 3.4 + STR)*(ATK + 2)/ATK - STR) / 3.4
x = (DEX + STR / 3.4)*(1 + 2/ATK) - STR / 3.4 - DEX
= (DEX + STR / 3.4)/ATK * 2
Or the above. lol
Oh. And technically speaking that's only maximum damage, though it won't make a huge difference.