# Math Help - a math exercise

1. ## a math exercise

Hey guys, I would need help with this exercise, I have the half of this exercise done, but I just need to figure out how to write it down on the PC Thx!

Oh, and x->~

~ wants to be infinity

2. ## Re: a math exercise

Originally Posted by Grobi93
Hey guys, I would need help with this exercise, I have the half of this exercise done, but I just need to figure out how to write it down on the PC Thx!

Oh, and x->~

~ wants to be infinity
Note that

$x - \sqrt{x^2 - 10x} = (x - \sqrt{x^2 - 10x}) \frac{(x + \sqrt{x^2 - 10x})}{x + \sqrt{x^2 - 10x}}$

$= \frac{10x}{x + \sqrt{x^2 - 10x}} = \frac{10}{1 + \sqrt{1 + \frac{10}{x}}}$