Question

3a +4b =2. 4a -4b =12 elimination

Answer 1

`3a+4b =2~~~....(i)\\\\4a-4b = 12~~~.....(ii)\\\\\\(ii) + (i)\\\\4a-4b +3a+4b = 12 +2\\\\\\\implies 7a = 14\\\\\implies a = \frac {14}7 = 2\\\\\\\text{Substitute a = 2 in equation (i):}\\\\3(2) +4b =2\\\\\implies 4b =2-6 = -4\\\\\implies b = - \frac44 =-1`

`\text{Hence,}~ (a,b) = (2,-1)`