(1)(-3x^2y)^3*xyz*(-1/3xy)^2=(-27x^6y^3)×xyz×1/9x^2y^2=-3x^9y^6z(2)(x-2y+4)(x+2y-4) =[x-(2y-4)][x+(2y-4)]=x²-(2y-4)²=x²-4y²+16y-16 (3)(-3)^0+(-1/2)^-2/l-2l=1+4/2=3