先化简,再求值x-2(1/4x-1/3y^2)+(-3/2x+1/3y^2),其中x=3/2,y=-2

来源:学生作业帮助网 编辑:作业帮 时间:2024/04/29 04:44:46

先化简,再求值x-2(1/4x-1/3y^2)+(-3/2x+1/3y^2),其中x=3/2,y=-2
先化简,再求值x-2(1/4x-1/3y^2)+(-3/2x+1/3y^2),其中x=3/2,y=-2

先化简,再求值x-2(1/4x-1/3y^2)+(-3/2x+1/3y^2),其中x=3/2,y=-2
x-2(1/4x-1/3y^2)+(-3/2x+1/3y^2)
=x-1/2x+2/3y^2-3/2x+1/3y^2
=-x+y^2
x=3/2,y=-2
那么
原式=-3/2+(-2)^2=-3/2+4=5/2=2.5

化简为:x-2/x+1/y^2
代入x,y的值得:x-2/x+1/y^2=3/2-4/3+1/4=5/12

x-2(1/4x-1/3y^2)+(-3/2x+1/3y^2)
=X-1/2X+2/3y²-3/2x+1/3y²
=x-1/2x-3/2x+2/3y²+1/3y²
=-x+y²
把x=3/2,y=-2代入得
上式=5/2