a) y²-y-2y+2=y(y-1)-2(y-1)=(y-1)(y-2)
b) a²y²-5a²y+6a²=a²(y²-2y-3y+6)=a²[y(y-2)-3(y-2)]=a²(y-2)(y-3)
c) xy(x-1)-2(x-1)=(x-1)(xy-2)
d) a²(1+b)-3a(1+b)=a(a-3)(1+b)
e) y(x²-6x+16)
din x²-6x+16=0 => Δ=36-64= -28 < 0 nu exista x1,x2 ∈R
f) y(x²+x+4x+4)=y[x(x+1)+4(x+1)]=y(x+1)(x+4)
g) x^4-5x²-6x²+30=x²(x²-5)-6(x²-5)=(x²-5)(x²-6)
