## Equations With Two Square Roots

Suppose we have an equation with two rots
$\sqrt{x+15}+ \sqrt{x}=15$
.
We can rearrange this to give
$\sqrt{x+15}= \sqrt{x}+15$
.
Now square both sides.
$x+15= x+30 \sqrt{x} +225$
.
Now
$x$
cancels from both sides, to give
$15= 30 \sqrt{x} +225 \rightarrow x = (\frac{15-225}{30})^2=49$
.