*I'm a bit confused with this qn*

Question

Expand and Simplify 3(3x-y)^2

Answer 1

3(3x-y)^2
= 3(3x-y)(3x-y)= 3(9x^2 - 3xy - 3xy + y^2)
= 27x^2 - 18xy + 3y^2