Math Help - simplifying a radical

wolfram|alpha says this is false but doesnt

$\sqrt{36-4x^2} \Rightarrow 2\sqrt{9-x^2}$

trueq[sqrt(36-4x^2) equals 2 Sqrt[9 - x^2]] - Wolfram|Alpha

Originally Posted by Jonroberts74
wolfram|alpha says this is false but doesnt
$\sqrt{36-4x^2} \Rightarrow 2\sqrt{9-x^2}$
trueq[sqrt(36-4x^2) equals 2 Sqrt[9 - x^2]] - Wolfram|Alpha
On the other hand, look at this.

And this.

why would it state it as false? Because, something subtracting something it equals is zero.