Ответы и объяснения

2013-09-14T14:47:13+04:00
1/x+1/(1+x)=((x+y)+x)/(x*(x+y)=(2x+y)/(x^2+xy)
x/(x+y)-(x-y)/x=(x^2-(x-y)*(x+y))/(x*(x+y)=(x^2-x^2+y^2)/(x^2+xy)=y^2/(x^2+xy)