Сократите дробь a^2-25/ab-5b-3a+15

Преобразуем знаменатель (ab-5b)-(3a-15) = b(a-5)-3(a-5) = (a-5)*(b-(a-5)*(a+5)/(a-5)*(b-3) = (a+5)/(b-3)

(a²-25)/(ab-5b-3a+15)=(a+5)(a-5)/(b(a-5)-3(a-5))= =(a+5)(a-5)/(a-5)(b-3)=(a+5)/(b-3)  a≠5,b≠3 a²-b²=(a+b)(a-b)