А) (х(х+1)-х)/(х+1)=(x^2+x-x)/(x+1)=x^2/(x+1)
б)=((m+2)(m+4)-4m) / (4m(m+4))=(m^2+6m+8-4m)/(4m(m+4)=(m^2+2m+8)/(4m^2+16m)
г) =(3x+y)/(x(x+y))-(x+3y)/(y(y+x))=((3xy+y^2-x^2-3xy)/(xy(x+y))=(y^2-x^2)/(xy(x+y))((y-x)(y+x))/(xy(x+y))=(y-x)/xy
в)=(x(x-y)+y(x+y)) /((x+y)(x-y))=(x^2-xy+xy+y^2)/(x^2-y^2)=(x^2+y^2)/(x^2-y^2)