1.2x*(1/2x^2-1)-3x(1/3x^2+2/3)
问题描述：
1.2x*(1/2x^2-1)-3x(1/3x^2+2/3)
2.3(y-z)^2-(2y+z)(-z+2y)
答
2x*(1/2x^2-1)-3x(1/3x^2+2/3)=x(x²-2)-x(x²+2)=x(x²-2-x²-2)=-4x3(y-z)^2-(2y+z)(-z+2y) =3y²-6yz+3z²-4y²+z²=4z²-6yz-y²没写错吗?