Select the variable cells as the “Changing Cells”
Press Add to add constraint(s)
(Note: you can add all adjacent constraint with same sign together)
Select left-hand-cell(s) as “Cell Reference”
Select sign for constraint(s)
Select right-hand-side cell(s) or enter constant as “Constraint”
Press Add to add another constraint or OK to return to Solver dialog box
Check the checkbox for “Make Unconstrained Variables Non-Negative”
Select Simplex LP as “Solving Method”