Hello Aditya, given can be rearranged as
y ( y^2 - 2 y ) - 2 ( y^2 - 2 y ) + ( y - 2)
Taking y^2 - 2y as common from the first two terms we have
(y^2 - 2 y) ( y -2) + ( y -2)
Now y-2 could be taken as common factor
So we get (y -2) ( y^2 - 2 y + 1 )
Or (y - 2) ( y - 1)^2
