设计电动机既能正转，也能反转的电路图

谁能帮我几道英语数学题, 题是 求3个equation的值 x1 x2 x3 为3个变量 但是中间有一步没看懂2*x1+4*x2-3*x3＝1x1+x2+2*x3 =93*x1+6*x2-5*x3=0Swapping the first and second equation,we have x1+x2+2*x3 =92*x1+4*x2-3*x3＝13*x1+6*x2-5*x3=0 Next,we subtract 2 lots of Find "a" the identity element and "b" inverse for the operation defined as "a*b=a+b+2"星号不是乘号···· 一道英语数学题,麻烦帮看一下,真的麻烦各位了,明天需要用到, 麻烦各位了,明天急用, the weights of egge produced on a farm are normally distributed with a mean of 1.4 ounces and a standard deviation of 0.4 ounces1.what percent of the eggs weight at least 1 ounce?2.how many of 1200 eggs are withiin 2 standard deviations of the mean?3 英语翻译In a run along the beach ,the girl who came two places in front of the last girl finished one place ahead of the girl who comes fifth.How many were running along the beach? 求翻译 ,一道英文数学题Mr Wang hasfive daughters.They are all born the number of years apart as the youngestdaughter is old.The oldest daughter is 16 years older than the youngest. Whatare the youngest of Mr Wang's daughter? 英语翻译the sum of 2 number is18.Express the product of the numbers as a function of the smaller number. 英语翻译A golfer is lining up a putt on a level green.The hole is 12 cm wide and the ball is 60 cm from the middle of the hole.Calculate the angle within which the ball can be hit into the hole 英语翻译if the number of square units in the area of circle C is twice the number of linear units of the circumference of C,what is the number of square units in the area? 英语翻译The measure of ∠1 is five less than four times the measure of ∠2.If ∠1 and ∠2 form a linear pair,what are their measures 英语：翻译句子：1.请为你的晚餐列一个食物清单.写出下面句子的一般疑问句：1.He is my brother's friend.2.She likes sandwiches.3.They like vegetable.4.I like bananas.5.His last name is Green.1.根据下列问题设未知 都不太明白.1、what is the difference between the value of 4 in 6471 and 4093?2,find the sum of the value of digit"2“ in 4025 and 2902.主要是不懂value of 4和value of digit”2“是什么意思,有什么区别.求中文翻译.1题中的d 一道英语数学题,求意思和答案Chongming Island stretches （ ）square kilometers from the East Sea on the east to the Yangtze River on the weast.A.12.25 B.122.5 C.1225 一道英语数学题,求意思和过程There is a line of five lattices.Please use three colour-red,green and black to dye them.Each lattice uses one colour.there are _____ways to dye them without two adjoint lattices both being green . the sum of the digits of two number is 12.the tens digits is twice the unit digit.find the number 一：王丽用一根绳子测树干的周长,第一次她将绳对着来量,绕树两周余一米；第二次将绳折成三折来量,绕树一周雨1.5米.请计算绳长,树干的周长各是多少?二：有粗细不同的两支蜡烛,细蜡烛长 英语数学题期待详解Felix converted（兑换）$924.00 to francs before his trip to France.At that time,each franc was worth thirty cents.If he returned from his trip with 21 francs,how many francs did he spend? 如右图,正方形ABCD边长为8,点M在DC上,且DM = 2,N是AC上一动点,则DN + MN的最小值为_______.图请去http://hi.baidu.com/kiss%D4%C2%CF%C2%CE%DE%C9%F1/album/item/0c5ee2376cf8b3f8a3cc2bb2.html观看这是图 仓库有一批货物,运走的货物与剩下的货物的质量比为2：7.如果又运走64吨,那么剩下的货物只有仓库原有货物的五分之三.仓库原有货物多少吨?我知道 算式是 2/（2+7）=2/9 64/（1-2/9-3/5） 第一个 加工一批零件,甲独做9时完成,乙独做6时完成.现在两人合作,完成任务时,甲做了72个零件,这批零件共有多少个? 有一根木料,第一次用去全长的百分之二十五,第二次用去5.2米,还剩下全长的四分之一没有用,这跟木料全长多少米?（算式和方程解,一本书共360页,明明第一周看了全书的四分之一,第二周和第 某种商品进货单价40元,若按每个50元的价格出售能卖出50个,若销售价每上涨一元,则销售量就减少一个,为获取最大利润,此商品的最佳售价应定为每个多少元?15、解不等式：|x2-3x-4| 求这道数学题答案 一台电视机如按标价降低百分之十,可盈利215元.如按标价降低百分之二十,便亏本125元.求标价是多少元? 小学六年级北师大数学题越多越好 给分! 一元一次方程解】某车间每天能生产甲种零件120个某车间每天能生产甲种零件120个,或乙种零件100个,甲、乙两种零件分别取3个、和2个才能配成一套,要在30天内生产最多的成套产品,问怎样安 某车间每天能生产甲种零件120个,或者乙种零件100个,或者丙种零件200个.甲、乙、丙三种零件分别取3个、2个、1个才能配成一套,要在30天内生产最多的成套产品,问：怎样安排生产甲、乙、丙两 数学题 分析思路 急!求直线过点p(2,-4)且与圆(x+1)^2+(y-2)^2=9相切的切线方程 2x(5-3x) (0小于X小于3分之5）求最大或最小值 一辆汽车从A地到B地,现已每小时72千米的速度行驶到距中点12千米处,加快了速度,以每小时80千米的速度行驶,又用同样多的时间到达B地.求A,B两地相距多少千米?