Y=(x²+3)/(x+1)
x+1≠0
x≠-1
x∈(-∞;-1) U (-1;∞)
y`=(2x(x+1)-1(x²+3))/(x+1)²=(2x²+2x-x²-3)/(x+1)²=(x²+2x-3)/(x+1)²=0
x²+2x-3=0
x1+x2=-2 U x1*x2=-3
x1=-3 U x2=1
+ _ _ +
-----------------(-3)------------(-1)--------(1)-----------------
возр max убыв убыв min возр
ymax=(9+3)/(-3+1)=-6
ymin=(1+3)/(1+1) =2
y∈(-∞;-6] U [2;∞)