Birinchidan, biz imkon qadar son va maxrajni ko'paytirishimiz kerak. Shunday qilib,

\[\frac{{{x^2} - 6x - 7}}{{{x^2} - 10x + 21}} = \frac{{\left( {x - 7} \right)\left( {x + 1} \right)}}{{\left( {x - 7} \right)\left( {x - 3} \right)}}\]

2-qadam

Endi biz qilishimiz kerak bo'lgan yagona narsa, ratsional ifodani eng past shartlarga qisqartirish uchun barcha omillarni bekor qilishdir.

\[\frac{{{x^2} - 6x - 7}}{{{x^2} - 10x + 21}} = \require{bbox} \bbox[2pt,border:1px solid black]{{\frac{{x + 1}}{{x - 3}}}}\]