化简求值:2xy^2-[3xy^2-2(x^2y-(1/2)xy^2)]-2x^2y其中x=-2/3,y=-1/2
人气:260 ℃ 时间:2019-12-08 13:16:56
解答
2xy^2-[3xy^2-2(x^2y-(1/2)xy^2)]-2x^2y
=2xy²-[4xy²-2x²y]-2x²y
=2xy²﹣4xy²﹢2x²y﹣2x²y
=﹣2xy²
=﹣2×﹙﹣2/3﹚﹙﹣1/2﹚
=﹣2/3﹣2×﹙﹣2/3﹚﹙﹣1/2﹚(﹣1/2﹚不是平方吗漏了2xy^2-[3xy^2-2(x^2y-(1/2)xy^2)]-2x^2y=2xy²-[4xy²-2x²y]-2x²y=2xy²﹣4xy²﹢2x²y﹣2x²y=﹣2xy²=﹣2×﹙﹣2/3﹚﹙﹣1/2﹚²=1/3
推荐
- 化简求值:1/2x^2y^3*(-3xy^2)+(-2xy)^2*xy^3+(1/4y)^2·(2xy)^3,其中x=1,y=-1
- 3x2y−[2xy2−2(xy−3/2x2y)+xy]+3xy2.
- 先化简,再求值:3xy^2-2(xy^2-3/2x^2y)+(3xy^2y-2xy^2) 其中x=-4 y=1/2
- 化简求职:2xy^2-[3xy^2-2(x^2y-(1/2)xy^2)]-2x^2y其中x=-2/3,y=-1/2
- 已知x-y=3,xy=-1,求(2x+3y-2xy)-(x+4y+xy)-(3xy+2y-2x)的值
- 谜语:一点一横一大撇,两个弯弯四小撇,左一撇右一撇,一撇一撇又一撇.
- 求给一篇的作文
- ★高二数学★椭圆c的中心在原点,左焦点F1,右焦点F2均在x轴上
猜你喜欢