ko'paytuvchilarga ajratishning dastlabki shakli quyidagicha bo'ladi:

\[\left( {z + \underline {\,\,\,\,\,} } \right)\left( {z + \underline {\,\,\,\,\,} } \right)\]

va 21 ning omillari,

\[\left( { - 1} \right)\left( { - 21} \right)\,\hspace{0.25in}\left( 1 \right)\left( {21} \right)\hspace{0.25in}\hspace{0.25in}\left( { - 3} \right)\left( { - 7} \right)\hspace{0.25in}\left( 3 \right)\left( 7 \right)\]

2-qadam

Endi eslatib o'tamizki, yuqoridagi ro'yxatdan -10 olish uchun qo'shiladigan juft omillar kerak. Shunday qilib, biz to'g'ri ko'paytuvchilarga ajratish bo'lishini ko'rishimiz mumkin,

\[{z^2} - 10z + 21 = \require{bbox} \bbox[2pt,border:1px solid black]{{\left( {z - 3} \right)\left( {z - 7} \right)}}\]