Question

( xy-1 )^ 2 - ( y-1 ) ^2
help pleaseeeeeeeeeeee

Answer 1

$(xy-1)^2-(y-1)^2\\\\=(xy - 1 - y+1)(xy-1+y-1)~~~~~~;[a^2-b^2 = (a-b)(a+b)]\\\\=(xy-y)(xy+y-2)\\\\=y(x-1)(xy+y-2)$