Given:
The expression is,
[tex](3x-3y)^2[/tex]Taking the expansion,
[tex]\begin{gathered} As\text{ we know,} \\ (a-b)^2=a^2-2ab+b^2 \\ (3x-3y)^2=(3x)^2-2\times(3x)\times(3y)+(3y)^2 \\ =9x^2-18xy+9y^2 \end{gathered}[/tex]Answer: The correct expansion for given expression is,
[tex](3x-3y)^2=9x^2-18xy+9y^2[/tex]