Упростить: 7/x^2-y^2-5/xy-x^2-12/x^2+xy
Знаменатели:X^2-y^2,xy-x^2,x^2+xy.

=7/(x-y)(x+y) +5/x(x-y) -12/x(x+y) =(7x+5(x+y) -12(x-y)) /x(x-y)(x+y) =(7x+5x+5y -12x +12y) /x(x-y)(x+y) =17y /x(x²-y²)ответ: 17y /x(x²-y²)