a. x-1≥0, x≥1
D(y)=[1;∞)
б. х-любое число
D(y)=(-∞;∞;)
в. x²-1≥0. (x-1)(x+1)≥0
+ - +
--------------|-----------|--------------->x
-1 1
D(y)=(-∞;-1]U[1;∞)
г. x²-4≠0, (x-2)(x+2)≠0
x≠-2, x≠2
D(y)=(-∞;-2)U(-2;2)U(2;∞)
д. {x²-x≥0
x²-x≠0 ⇒x²-x>0
x(x-1)>0
+ - +
-----------0---------1-------->x
D(y)=(-∞;0)U(1;∞)
e. x+4≠0, x≠-4
D(y)=(-∞;-4)U(-4;∞)