Answer
$(x^2+1)\sqrt{x+1}-\sqrt{(x+1)^3}=x(x-1)\sqrt{x+1}$
Work Step by Step
$(x^2+1)\sqrt{x+1}-\sqrt{(x+1)^3}$
$(x^2+1)\sqrt{x+1}-\sqrt{(x+1)^2(x+1)}=(x^2+1)\sqrt{x+1}-(x+1)\sqrt{x+1}$
$(x^2+1-(x+1))\sqrt{x+1}=(x^2-x)\sqrt{x+1}=x(x-1)\sqrt{x+1}$
