Show that there is a point on the line through (2,0,0) & (0,5,0) and that is nearest to the line x=u, y=u, z=u.

Let's see if I understood: the line through , and apparently the other line is just , so take a general point in the first line and evaluate its distance from a general point of the second line (Apparently you don't know yet/you can't use , the well known formula for the distance of a given point from a given line): , but of course the max.-min. points of the above are the same without the square root (why?), so define and show there's a unique solution to (I think it is ...) Tonio
I started by creating a function, F(x) = cx + d, where that f(c,d) = The sum from 1 to n of (cx_i + b - y_i)^(2) so I could minimize it. However, I just keep coming up blanks.