Answer
$8$
Work Step by Step
Add $3$ to both sides:
$3\sqrt{2x}-3+3=9+3$
$3\sqrt{2x}=12$
Divide both sides by $3$:
$\dfrac{3\sqrt{2x}}{3}=\dfrac{12}3$
$\sqrt{2x}=4$
Square both sides:
$(\sqrt{2x})^2=4^2$
$2x=16$
Divide both sides by $2$:
$\dfrac{2x}2=\dfrac{16}2$
$x=8$
Substitute into original problem to check for extraneous solutions:
$3\sqrt{2(8)}-3=9$
$3\sqrt{16}-3=9$
$3(4)-3=9$
$12-3=9$
$9=9$
