Answer:
Complete expression will be [tex](x-y)^2-9[/tex]
Step-by-step explanation:
We have given expression [tex][(x-y)-3][(x-y)+3]=(....)^2-9[/tex]
We have to complete the expression
We know the algebraic equation [tex](a+b)(a-b)=a^2-b^2[/tex]
So[tex][(x-y)-3][(x-y)+3][/tex] can be written as [tex](x-y)^2-9[/tex]
So in place of blank space there will be [tex](x-y)^2[/tex]
And the complete expression will be [tex](x-y)^2-9[/tex]