Question

Factorise : $(x-2y{)}^2-12(x-2y)+32$

Answer 1

$Let(x-2y)=a\therefore (x-2y{)}^2=a^2\therefore (x-2y{)}^2-12(x-2y)+32=a^2-12a+32=a^2-8a-4a+32=a(a-8)-4(a-8)=(a-8)(a-4)=(x-2y-8)(x-2y-4)$