our instructor gave us this problem as a heads up because it will be on our quiz tomorrow, but it is pretty tough. He told us to multiply by the conjugate...

lim (x^2+x)^1/2 + x

x -> (infinite)

I have determined that the conjugate is (x^2+x)^1/2 - x, but when i do that, and then to L'hopital's, i feel as tho continuing will get me nowhere... help?