{(x+1)(x-4)≥0
{(x+1)(x-3)>0
1) (x+1)(x-4)≥0
x=-1 x=4
+ - +
------ -1 ---------- 4 ----------
\\\\\\\\ \\\\\\\\\\\\\
x∈(-∞; -1]U[4; +∞)
2) (x+1)(x-3)>0
x= -1 x=3
+ - +
-------- -1 ---------- 3 ------------
\\\\\\\\\\\ \\\\\\\\\\\\\
x∈(-∞; -1)U(3; +∞)
{x∈(-∞; -1]U[4; +∞)
{x∈(-∞; -1)U(3; +∞)
x∈(-∞; -1)U[4; +∞)
D(y)=(-∞; -1)U[4; +∞) - область определения.