#### Answer

At $x=2~m$:
$F_x = 2.5~N$
At $x=5~m$:
$F_x = 0.40~N$
At $x=8~m$:
$F_x = 0.16~N$

#### Work Step by Step

$U = \frac{10}{x}~J$
We can find an expression for $F_x$:
$F_x = -\frac{dU}{dx}$
$F_x = -(-\frac{10}{x^2})~N$
$F_x = \frac{10}{x^2}~N$
We can find $F_x$ at $x = 2~m$:
$F_x = \frac{10}{x^2}~N$
$F_x = \frac{10}{2^2}~N$
$F_x = 2.5~N$
We can find $F_x$ at $x = 5~m$:
$F_x = \frac{10}{x^2}~N$
$F_x = \frac{10}{5^2}~N$
$F_x = 0.40~N$
We can find $F_x$ at $x = 8~m$:
$F_x = \frac{10}{x^2}~N$
$F_x = \frac{10}{8^2}~N$
$F_x = 0.16~N$