求助求助大佬，答案=-1，是-无穷，谢谢😊

lim(x->-∞) [√(x^2+2x) +x]
y=-x
=lim(y->+∞) [√(y^2-2y) -y]
=lim(y->+∞) [(y^2-2y) -y^2]/[√(y^2-2y) +y]
=lim(y->+∞) -2y/[√(y^2-2y) +y]
=lim(y->+∞) -21/[√(1-2/y) +1]
=-2/(1+1)
=-1