Question

как это делать подскажите ?

Answer 1

1. (x+y)/y × (x/(x+y) - (x-y)/x) = x(x+y) / y(x+y) - (x+y)(x-y) / xy =
 = x/y - (x²-y²)/xy = (x²-x²+y²)/xy = y²/xy = y/x