Answer
$x=50$
Work Step by Step
$-\sqrt {2x}+4=-6$
$-\sqrt {2x}+4-4=-6-4$
$-\sqrt {2x}=-10$
$-1*-\sqrt {2x}=-10*-1$
$\sqrt {2x}=10$
$(\sqrt {2x})^2=10^2$
$2x=100$
$2x/2=100/2$
$x=50$
$-\sqrt {2x}+4=-6$
$-\sqrt {2*50}+4=-6$
$-\sqrt {100}+4=-6$
$-10+4=-6$
$-6=-6$ (true)