Solve for $x$ in $\sqrt{3.5^2+x^2}-\sqrt{3.0^2+x^2}=0.25$ I am taking physics right now and I have gotten my problem down to the following equation:
$$\sqrt{3.5^2+x^2}-\sqrt{3.0^2+x^2}=0.25$$
I am looking for some guidance as to what to do with the square roots in order to solve for $x$. I know I can't take the square of both sides and I tried to factor and failed.

\begin{align} 
& \sqrt{3.5^2+x^2}-\sqrt{3.0^2+x^2}=.25 \\
& \sqrt{3.5^2+x^2}=.25+\sqrt{3.0^2+x^2} \\
\end{align}
Next, square both sides. You get:
\begin{align}
& 3.5^2+x^2=(.25+\sqrt{3.0^2+x^2})^2 \\
3.5^2+x^2=.0625+.50(\sqrt{3.0^2+x^2})+3.0^2+x^2
\end{align}
Simplifying further gets you: $3.1875=.50(\sqrt{3.0^2+x^2})$, $6.375=\sqrt{3.0^2+x^2}$. 
$x≈±5.62$ 
