The following LPP problem has Zmin = 1.5x₁ + 4.5x₂ Subject to x₁ + 3x₂ > 3 x₁ + x₂ > 2 x₁, x₂ > 0
We can see that we verify Alternate optimal solution by full calculation: use standard identity, substitute, simplify step by step to reach Alternate optimal solution.
Ref: NCERT Mathematics Class XII — Linear Programming