ýòîì ñëó÷àå íà ïåðåìåííóþ x2 íå íàêëàäûâàåòñÿ îãðàíè÷åíèå íåîòðèöàòåëüíîñòè. Ââåäÿ äâå íîâûå íåîòðèöàòåëüíûå ïåðåìåííûå x2+≥0, x2–≥0, èñõîäíóþ ïåðåìåííóþ x2 ìîæíî èñêëþ÷èòü ïóò¸ì çàìåíû: x2 = x2+ – x2–.
Öåëåâàÿ ôóíêöèÿ áóäåò èìåòü âèä:
max z = 13x1 – 20(x2+ – x2–).
Ïîñëå ðàñêðûòèÿ ñêîáîê:
max z = 13x1 – 20x2+ + 20x2–.
Òàê êàê ïåðâîå îãðàíè÷åíèå èìååò çíàê “≤”, òî â ëåâóþ ÷àñòü îãðàíè÷åíèÿ ââîäèì îñòàòî÷íóþ ïåðåìåííóþ s1, à âìåñòî ïåðåìåííîé x2 ïîäñòàâëÿåì ðàçíîñòü: x2+ – x2–. Ïîëó÷èì ñèñòåìó:
x1 + 2x2+ – 2x2– + s1 = 6,
s1 ≥ 0.
Âòîðîå îãðàíè÷åíèå èìååò çíàê “≥”, çíà÷èò â ëåâóþ ÷àñòü îãðàíè÷åíèÿ ââîäèì èçáûòî÷íóþ ïåðåìåííóþ s2, à âìåñòî ïåðåìåííîé x2, êàê â è ïðåäûäóùåì îãðàíè÷åíèè, ïîäñòàâëÿåì ðàçíîñòü:
-2x1 + 7x2+ – 7x2– – s2 = 8,
s2 ≥ 0.
Èòàê, êàíîíè÷åñêàÿ ôîðìà ïîñëå âñåõ ïðåîáðàçîâàíèé èìååò âèä:
max z = 13x1 – 20x2+ + 20x2– + 0s1 + 0s2 → max,
x1 + 2x2+ – 2x2– + s1 = 6,
-2x1 + 7x2+ – 7x2– – s2 = 8,
x1, x2+, x2– , s1, s2, ≥ 0.