Question

Which of the following is the correct expansion of (3x - 3y)^2?9 x^2 - 18 xy + 9 y^29 x^2 - 9 y^29 x^2 + 9 y^29 x^2 + 18 xy + 9 y^2

Answer 1

Given:

The expression is,

`(3x-3y)^2`

Taking the expansion,

`\begin{gathered} As\text{ we know,} \\ (a-b)^2=a^2-2ab+b^2 \\ (3x-3y)^2=(3x)^2-2*(3x)*(3y)+(3y)^2 \\ =9x^2-18xy+9y^2 \end{gathered}`

Answer: The correct expansion for given expression is,

`(3x-3y)^2=9x^2-18xy+9y^2`