(-3xy-7y)+[4x-3(xy+y-2x)],其中xy=-2,x-y=3,先化简,再求值.
人气：110 ℃ 时间：2019-08-21 15:28:07
解答
(-3xy-7y)+[4x-3(xy+y-2x)],
=-3xy-7y+4x-3xy-3y+6x
=-6xy+10x-10y
=-6xy+10(x-y) xy=-2,x-y=3
=-6×(-2)+10×3
=18+30
=48
推荐
- 已知xy=-2，x-y=3，求整式（-3xy-7y）+[4x-3（xy+y-2x）]的值．
- 已知xy=-2，x-y=3，求整式（-3xy-7y）+[4x-3（xy+y-2x）]的值．
- 已知xy=﹣2,x－y=3,求代数式﹙3xy－7y﹚＋[4x－﹙3xy－y－2x﹚]的值
- (3/2x^2-5xy+y^2)-[-3xy+2(1/4x^2-xy)+2/3y^2],其中x=1,y=-2 化简求值
- 已知x-y=5，xy=3，则3xy-7x+7y=_．
- 1选A,2选B,我不确定答案,
- Would you like to fly a kite with me?Sorry,I h_______ ever have time for a game
- 取三支干净的小试管,试管A盛有开始蒸馏出的液体,试管B装有蒸馏一段时间后收集的,试管C放入没蒸馏的硬水
猜你喜欢
