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2(x^2y+xy)-3(x^2y-xy)-4x^2y,其中x=1,y=-1.（写过程） 还有吗？
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第1个回答 2022-08-25
2(x^2y+xy)-3(x^2y-xy)-4x^2y
=2x^2y+2xy-3x^2y+3xy-4x^2y
=-5x^2y+5xy
=-5xy(y-1)
=-5*1*(-1)*(-1-1)
=-10
相似回答
2(x^2y+xy)-3(x^2y-xy)-4x^2y,其中x=1,y=-1.(写过程)
答：
2(x^2y+xy)-3(x^2y
+
xy)-4x^2y
=2x^2y+2xy-3x^2y+3xy-4x^2y =2x^2y-3x^2y-4x^2y+2x
y+3x
y =-5x^2y+5xy 当
x=1,,y=-1
时,,-5×1^2×（-1）+1×1=4 呜呜~手打得很累滴,,~~~
①化简求值:
2(x^2y+xy)-3(x^2y-xy)-4x^2y,其中x=1,y=-1
.
答：
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+m...
化简求值
2(x^
2
+xy)-3(x^2y-xy)-4x^2y其中x=1,y=-1
答：
2(x^
2
+xy)-3(x^2y-xy)-4x^2y其中x=1,y=-1
=2x²+2xy-3x²
y+3x
y-4x²y =2x²+5xy-7x²y =2*1²+5*1*(-1)-7*1²*(-1)=2-5+7 =4 2x^3+4x-1/3x^2-(x+3x^2-2x^3)
,其中x=
-3 =2x³+4x-1/3x²-x-3x&#...
...
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
...
答：
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
(x^2y+xy)-3(x^2y-xy)-4x^2y
化简
其中x=1
y=-1
答：
2(x^2y+xy)-3(x^2y-xy)-4x^2y =
2x²y+2xy-3x²y+3xy-4x² y =-5x²y+5xy =5-5 =0
初一数学!求解!谢谢!
答：
2（x
∧
2y+xy）-3（x
∧
2y-xy）-4x
∧2y 化简＝2x∧2y+2xy-3x∧2y+3xy-4x∧2y ＝-5x∧2y+5xy 带入x＝-
2，y＝1
/2，得到（-5）×（-2）∧2×1/2+5×（-2）×1/2 ＝（-5）×4×1/2+5×（-2）×1/2 ＝-10-5 ＝-15 ...
2(
2
x^2y
-
3xy)
-
(xy+4x2y), 其中 x=1 , y=-1?
答：
方法如下，请作参考：
3(
2
x^2y-xy
^
2)
-
(4x
y^
2+
3
x^2y)其中x=-1y=2
答：
解由3(2
x^2y-xy
^
2)
-
(4x
y^2+3
x^2y)=
6x^2y-3xy^2-4xy^2-3
x^2y =
6x^2y-3x^2y-3xy^2-4xy^2 =3x^2y-7xy^2
=3（
-
1）
^2×2-7（-1）×2^2 =6+28 =34
3(x^2
-
2y-xy)
-[3x^2-2y-
2(xy+y)
]
,其中x=-1
完整
过程
答：
3(x^
2-
2y-xy)
-[3x^2-2y-
2(xy+
y)]=3x²-6y-3xy-(3x²-2y-2xy-
2y)=
3x²-6y-3xy-3x²+4y+2
xy =
-2y-xy
大家正在搜
(x+y)(x²-xy+y²)
(2x+y)²-(x+2y)²
xy'+y=x^2+3x+2
xy'+y=y(lnx+lny)
x+y+xy=54求x+y
xy/x^2+y^2的极限
x^2+y^2=1
xy'+2y=xlnx
2^xy=x+y