已知x=-3,y=1/3,求-x^2-(3/2x^2-1/3y)+(2/3-2x^2)

问题描述:

已知x=-3,y=1/3,求-x^2-(3/2x^2-1/3y)+(2/3-2x^2)

原式=-9/2*9+1/3*1/3+2/3
=-715/18

原式=-x^-3/2x^+1/3y+2/3-2x^
=-3x^-3/2x^+1/3y+2/3
=(-3-2/3)x^+1/3y+2/3
=-9/2*9+1/3*1/3+2/3
=-81/2+1/9+2/3
=-81/2+5/9
=-729/18+10/18
=-719/18

原式=-x^2-3/2x^2+1/3y+2/3-2x^2
=-9/2x^2+1/3y+2/3
把x=-3,y=1/3带入
x^2=9
原式=-9/2*9+1/3*1/3+2/3
=-715/18