Сократите дробь a^2-4a-5/a^2-9a+20

Question

Сократите дробь a^2-4a-5/a^2-9a+20

Answer 1

А²-4а-5=0
D=36
a1=-1 
a2=5
a²-4a-5=(a+1)(a-5)
a²-9a+20=0
D=1
a1=4
a2=5
a²-9a+20=(a-4)(a-5)
a²-4a-5 / a²-9a+20 = (a+1)(a-5) / (a-4)(a-5) = a+1 / a-4