(1)已知x+y=6,xy=-3,x^2y+xy^2=

(1)已知x+y=6, xy=-3 x^2y+xy^2 =xy(x+y) =-3*6 =-18 (2)x*[2-(1/x)]+(x/x^2-2x)*(x^2-4) =x*(2x-1)/x+[x/x(x-2)]*(x+2)(x-2) =(2x-1)+(x+2)(x-2)/(x-2) =2x-1+x+2 =3x+1