Перезалив............

1
x³-x²+4x+C
2

3
f`(x)=(1*(x+2)-1*x)/(x+2)²=(x+2-x)/(x+2)²=2/(x+2)²
f``(x)=-4/(x+3)³
4
lim[(x²-5)/(-2x-3)]=(1-5)/(-2-3)=0,8
x→1