图
=2x²y+2xy-3x²y+3xy-4x²y
=-5x²y+5xy
=-5x1²x（-1）+5x1x（-1）
=5-5
=0本回答被网友采纳
先化简,再求值。2(x的平方y+xy)-3(x的平方y-xy)-4x的平方y,其中x=1,y...
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先化简,再求值:2(x 2 y+xy)-3(x 2 y-xy)-4x 2 y ,其中x=-1,y=1。
解：原式 当 ， 时，原式
...一3(x的平方y一xy)一4x的平方y,其中x=负1,y=1
-10
化简求值:2(x的平方y+xy)-3(x的平方y-xy)-4x的平方y,其中x=1,y=负1
2(x的平方y+xy)-3(x的平方y-xy)-4x的平方y =2x²y+2xy-3x²y+3xy-4x²y =-5x²y+5xy =5x1²x1-5x1x1 =0
先化简,再求值:2(x^2 y+xy)-3(x^2 y-xy)-4x^2 y,其中x=-1,y=1
2(x^2 y+xy)-3(x^2 y-xy)-4x^2 y，=2x²y+2xy-3x²y+3xy-4x²y =-5x²y+5xy =-5x（-1）²x1+5x（-1）x1²=-5-5 =-10
先化简,再求值:2(x²y+xy)-3(x²y-xy)-4x²y,期中x=-1,y=1\/3
=2x²y+2xy-3x²y+3xy-4x²y =-5x²y+5xy x=-1，y=1\/3 原式=-5x(-1)²x 1\/3 +5x(-1)x 1\/3=-10\/3 请采纳
...2(x²y+xy)-3(x²y-xy)-4x²y 其中x=-1,y=1
你好~首先去掉括号化简 2（x²y+xy）-3（x²y-xy）-4x²y =2x²y+2xy-3x²y+3xy-4x²y =2x²y-3x²y-4x²y+2xy+3xy =-5x²y+5xy =5xy(-x+1)=5(-1)(1)(1+1)=-10 祝你学习进步 ...
先化简,再求值:2(x²y+xy)-3(x²y-xy)-4x²y,其中x=-1,y=1。
2x²y+2xy-3x²y+3xy-4x²y -5x²y+5xy 则 -5×(-1)²×1+5×(-1)×1 -10
...2次方乘y+xy)-3(x的2次方乘y-xy)-4x的 2次方乘y,其中x=1,y=-1...
2(x^2y+xy)-3(x^2y-xy)-4x^2y =2x^2y+2xy-3x^2y+3xy-4x^2y =-5x^2y+5xy x=1，y=-1 =-5*1*(-1)+5(-1)*1 =5-5=0 ~望采纳
①化简求值:2(x^2y+xy)-3(x^2y-xy)-4x^2y,其中x=1,y=-1.
2(x^2y+xy)-3(x^2y-xy)-4x^2y =2x²y+2xy-3x²y+3xy-4x² y =-5x²y+5xy =5-5 =0 (3x^2+my-8)-(-nx^2+2y+7)=3x²+my-8+nx²-2y-7 =(3+n)x²+(m-2)y-15 ∵不含有x，y ∴3+n=0 m-2=0 ∴m=2 n=-3 ∴n^m+...
