Evaluate $z=2x+3y$ at each corner point.
At $(2,0)$
$z=2(2)+3(0)=4$
At $(7,0)$
$z=2(7)+3(0)=14$
At $(4,5)$
$z=2(4)+3(5)=8+15=23$
At $(0,3)$
$z=2(0)+3(3)=9$
Maximum value of $z=23$
Minimum value of $z=4$
Difference
$23-4=19$
The corner points of the feasible region determined by x + y ≤ 8, 2x + y ≥ 8, x ≥ 0, y ≥ 0 are A(0, 8), B(4, 0), and C(8, 0). If the objective function Z = ax + by has its maximum value on the line segment AB, then the relation between a and b is: