stuck with this problem help!

Plug in x first.
[tex] 2(2)\sqrt{18(2)} + 3(2)\sqrt{2(2)}\\ \\4\sqrt{36} + 6\sqrt{4} [/tex]
Now you can simplify. After finding the square root multiply it by the number outside of the radical.
[tex] \sqrt{36} = 6 * 4 = 24\\\sqrt{4} = 2 * 6 = 12 [/tex]
Add those together.
24 + 12 = 36.