Question

yes thank you

$(3x-3)^2 = 9x^2-18x+9$

Do you understand how I opened the brackets  ??

no I'm not sure how you got to the answer

Ok.

To open a square brackets follow this 

1 - square the first term    ( in this question the first term is " 3x " so $(3x)^2 = 3^2*x^2 = 9x^2$) 

2 - Multiply the power which is alwayse " 2 " with the two terms ( In this qestion $2 * 3x * -3 = -18x$ ) 

3 - square the second term ( In this question the second term is " -3 " so $(-3)^2 = 9$

4 - gather your answer 

$(3x-3)^2 = 9x2 - 18x + 9$

do you get it? 

You are welcome