Sagot :
[tex]\sqrt{18x^3}-\sqrt{9x^3}+3\sqrt{x^3}-\sqrt{2x^3}\\\\=\sqrt{9x^2\cdot2x}-\sqrt{9x^2\cdot x}+3\sqrt{x^2\cdot x}-\sqrt{x^2\cdot2x}\\\\=3x\sqrt{2x}-3x\sqrt{x}+3x\sqrt{x}-x\sqrt{2x}=2x\sqrt{x}\\\\Answer:C.[/tex]
[tex]\sqrt{18x^3}-\sqrt{9x^3}+3\sqrt{x^3}-\sqrt{2x^3}=\\
3\sqrt{2x^3}-3\sqrt{x^3}+3\sqrt{x^3}-\sqrt{2x^3}=\\
2\sqrt{2x^3}=\\
2x\sqrt{2x}\Rightarrow C[/tex]