An objective function is given by Z(x₁, x₂) = 3x₁ + 9x₂ The constraints are: x₁ + x₂ ≤ 8; x₁ + 2x₂ ≤ 4; x₁ ≥ 0; x₂ ≥ 0 W
Simply put, complete solution: write formula, plug data, do arithmetic. Final value matches 18. Simple and accurate.
Ref: NCERT Mathematics Class XII — Linear Programming