(-a-3)x²+6x+4a=0,
-a-3≠0, a≠-3;
D₁=k²-ac=3²-(-a-3)·4a=9+4a(a+3)=4a²+12a+9=(2a)²+2·2a·3+3²=(2a+3)²,
x=(-k±√D1)/a
x₁=(-3+√(2a+3)²)/(-a-3),
x₂=(-3-√(2a+3)²)/(-a-3).
2a+3≥0, a≥-1,5,
x₁=(-3+2a+3)/(-a-3)=-2a/(a+3),
x₂=(-3-(2a+3))/(-a-3)=(2a+6)/(a+3)=2(a+3)/(a+3)=2.
a<1,5,</p>
x₁=(-3-(2a+3))/(-a-3)=2,
x₂=(-3+(2a+3))/(-a-3)=-2a/(a+3).
a=-3,
6x+4·(-3)=0,
6x-12=0,
6x=12,
x=2.