Max z = x₁ + x₂ subject to constraints: x₁ + x₂ ≤ 1 -3x₁ + x₂ ≥ 3 x₁, x₂ ≥ 0
Understanding this is easy: after simplifying, Infeasible solution is left. The method is simple: formula → substitution → calculation → answer.
Ref: NCERT Mathematics Class XII — Linear Programming