aratati ca nr a=(x+6)(x-1)+x+15 este patrat perfect oricare ar fi a

Răspuns :

a = (x+6)(x-1)+x+15
a=x²-x+6x-6+x+15
a=x²+6x+9
a= (x+3)²
x²+6x-x-6+x+15=x²+6x+9=(x+3)², p.p.
as simple as that!!