D=4+60=64=8^(2),
x=(–2 ± 8)/2,
x_(1)=–5, x_(2)=3;
3x^(2)+30x–33=0,
D/4=225+99=324=18^(2),
x=(–15 ± 18)/3,
x-(1)=–11, x_(2)=1;
{(x+5)(x–3)>0,
{3(x+11)(x–1) ≥ 0;
{(x+5)(x–3)>0,
{(x+11)(x–1) ≥ 0;
{x<–5 или x>3,
{x ≤ –11 или x ≥ 1;
x ≤ –11 или x>3,
x ∈ (– ∞;–11] ∪ (3;+ ∞ ).