[tex]3a+4b =2~~~....(i)\\\\4a-4b = 12~~~.....(ii)\\\\\\(ii) + (i)\\\\4a-4b +3a+4b = 12 +2\\\\\\\implies 7a = 14\\\\\implies a = \dfrac {14}7 = 2\\\\\\\text{Substitute a = 2 in equation (i):}\\\\3(2) +4b =2\\\\\implies 4b =2-6 = -4\\\\\implies b = - \dfrac44 =-1[/tex]
[tex]\text{Hence,}~ (a,b) = (2,-1)[/tex]
