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Graphical method max:Z=5x₁+3x₂

Short answer

Plot constraints x1+2x2≤50, 2x1+x2≤40, x1,x2≥0. Corner points: (0,0), (20,0), (10,20), (0,25). Max Z=5x1+3x2 is 110 at (10,20).

Graphically maximize Z = 5x₁ + 3x₂ subject to the constraints x₁ + 2x₂ ≤ 50, 2x₁ + x₂ ≤ 40, x₁, x₂ ≥ 0.

Step 1: Draw the constraint lines. Replace each inequality by an equation, find the intercepts and decide which side of the line is allowed (test the origin).

ConstraintLineMeets x-axisMeets y-axisAllowed side
(1) x₁ + 2x₂ ≤ 50x₁ + 2x₂ = 50(50, 0)(0, 25)towards the origin
(2) 2x₁ + x₂ ≤ 402x₁ + x₂ = 40(20, 0)(0, 40)towards the origin

Also x₁ ≥ 0 and x₂ ≥ 0, so the region lies in the first quadrant.

Step 2: Feasible region. The region satisfying all constraints is the shaded polygon below (dots), with corner points marked A, B, C, ….

  29|                                            
    |                                            
    |D                                           
    |......                                      
    |.............                               
    |...................C                        
    |.....................                       
    |.......................                     
    |........................                    
    |..........................                  
    |............................                
    |.............................               
    |...............................             
    |.................................           
    |...................................         
    |....................................        
   0|A....................................B      
    +--------------------------------------------
     0                                         23

Step 3: Corner points and the objective value. The optimum of a linear function over a convex polygon occurs at a corner point.

PointCoordinatesLines meeting thereZ = 5x₁ + 3x₂
A(0, 0)x₁ = 0, x₂ = 00
B(20, 0)(2), x₂ = 0100
C(10, 20)(1), (2)110
D(0, 25)(1), x₁ = 075

Step 4: Conclusion. The largest value of Z is 110, at C(10, 20).

Answer: Maximum Z = 110 at x₁ = 10, x₂ = 20.

✓ Answer checked by Claude Opus 5.5 (high effort)

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