I'm a little put off by the wording on this question, if anyone can offer some guidance on how to begin that would be great. also, sorry if i enter the symbols wrong, i'm new here. i don't know why the square root symbol isn't covering all of $\displaystyle x^2 +7$ , but it should.

"find the x-coordinates of the points on the graph where the tangent line is horizontal"

$\displaystyle

f(x) = \frac{x}{\sqrt(x^2 +7)}$