Question

Помогите пж один пример)

Answer 1

$tt (y+(y-1):(y+1))(y-(y+1):(y-1))=bigg(y+dfrac{y-1}{y+1}bigg)bigg(y-dfrac{y+1}{y-1}bigg)=\ \ =dfrac{y^2+y+y-1}{y+1}cdotdfrac{y^2-y-y-1}{y-1}=dfrac{y^2+2y-1}{y+1}cdotdfrac{y^2-2y-1}{y-1}=\ \ \ =dfrac{(y^2+2y-1)(y^2-2y-1)}{y^2-1}$