mwbr.net
当前位置:首页 >> 先化简再求值2x^2y%4xy^2%2分之1xy^2 x^2y其中x=负... >>

先化简再求值2x^2y%4xy^2%2分之1xy^2 x^2y其中x=负...

题干不清晰,无法正常作答

(1)原式=3a-8a+2-3+4a=-a-1,代入a=-12可得:原式=-a-1=-12.(2)原式=2x2y-4xy2+3xy2-x2y=x2y-4xy2,将x=-1,y=2代入得:原式=x2y-4xy2=18.

解:(x+y)(x-y)+(2x的三次方y-4xy的三次方)÷2xy       =x²-y²+(2x³y-4xy³)÷2xy       =x²-y²+x²-2y²       =2x²-3y² 把x=-1,y=2代入化简后...

希望对你有所帮助 还望采纳~~~

若(x-2)的平方+|y-1|=0, 则x-2=0 x=2 y-1=0 y=1 4xy-(2x的平方+5xy-y的平方)+2(x的平方+3xy) =4xy-2x²-5xy+y²+2x²+6xy =5xy+y² =5×2×1+1 =11

%……

x的二次方y-xy的二次方-(2x的二次方+4xy+2y的二次方) =x²y-xy²-(2x²+4xy+2y²) =xy(x-y)-2(x+y)² 已知x-y=-3,x+y=1; (x+y)²-(x-y)²=1-9=-8=4xy; xy=-2; 原式=(-2)(-3)-2*1*1=6-2=4;

1.已知曲线C:x^2+4xy+5y^2=1,求dy/dx并由此,求与直线y=(-1/2)x平行且与c相切的两直线的方程。 2.设y=x+sin2x,其中0

5xy2-2x2y+[3xy2-(4xy2-2x2y)],=5xy2-2x2y+3xy2-4xy2+2x2y,=4xy2当x=-2,y=-1时,代入上式得:原式=4×(-2)×(-1)2=-8

(1)原式=-2x2+6x+6x2-4x-1=4x2+2x-1,当x=-4时,原式=64-8-1=55;(2)原式=4xy-x2-5xy+y2+2x2+6xy-y2=x2+5xy,当x=-1,y=2时,原式=1-10=-9.

网站首页 | 网站地图
All rights reserved Powered by www.mwbr.net
copyright ©right 2010-2021。
内容来自网络,如有侵犯请联系客服。zhit325@qq.com