回答下面的数学题,要准确率,不要跑堂,X已知X²+3X+1=0,求(1)x+1/x,(2)x²+1/x²+2x+2/x的值前面一个x是多打的

来源:学生作业帮助网 编辑:六六作业网 时间:2024/12/22 23:13:16
回答下面的数学题,要准确率,不要跑堂,X已知X²+3X+1=0,求(1)x+1/x,(2)x²+1/x²+2x+2/x的值前面一个x是多打的回答下面的数学题,要准确率,不

回答下面的数学题,要准确率,不要跑堂,X已知X²+3X+1=0,求(1)x+1/x,(2)x²+1/x²+2x+2/x的值前面一个x是多打的
回答下面的数学题,要准确率,不要跑堂,
X已知X²+3X+1=0,求(1)x+1/x,(2)x²+1/x²+2x+2/x的值
前面一个x是多打的

回答下面的数学题,要准确率,不要跑堂,X已知X²+3X+1=0,求(1)x+1/x,(2)x²+1/x²+2x+2/x的值前面一个x是多打的
(1)将方程X²+3X+1=0两边同时除以x得:x+3+1/x=0 ∴x+1/X=-3
(2)将方程x+1/X=-3两边平方得:x²+2+1/x²=9
∴x²+1/x²=7
∴x²+1/x²+2x+2/x=7-2×3=1

???

(1)将方程X²+3X+1=0两边同时除以x得: x+3+1/x=0 ∴x+1/X=-3
(2)将方程x+1/X=-3两边平方得:x²+2+1/x²=9
∴x²+1/x²=7
∴x&#...

全部展开

(1)将方程X²+3X+1=0两边同时除以x得: x+3+1/x=0 ∴x+1/X=-3
(2)将方程x+1/X=-3两边平方得:x²+2+1/x²=9
∴x²+1/x²=7
∴x²+1/x²+2x+2/x=7-2×3=1

收起

第一题:两边同除x得-3
第二题:由一知x+1/x=-3,取平方得x²+1/x²=7,2x+2/x得-6,综上,得1。

(1). x+3+1/x=0(两边同时除以x),所以x+1/x=-3
(2). x^2+1/(x^2)=(x+1/x)^2-2=7
所以为7-2*3=1

(1)把原试同时除以一个x,达到x+3+1/x=0,所以x+1/x=-3
(2)把x+1/x平方后得到x*2+2+1/x*2=9,所以x*2+1/x*2=7
然后把x+1/x乘以2得到2x+2/x=-6,所以原式的值为7-6=1
(打不来平方符号,敬请谅解)

(1).将式子除以一个x,得x+3 1/x=0所以,x 1/x=-3 (2).将式子分为两个部分求。=(x²+1/x²) 2(x 1/x),后面的一部分已经由第一问可得了,第一部分是将x 1/x平方一下,就可以得到x² 1/x²=7,所以之和为1。

方程X²+3X+1=0两边同时除以x
则(1)x+1/x=-3
(2)原式=(x+1/x)^2-2+2(x+1/x)
=9-2-6
=1

回答下面的数学题,要准确率,不要跑堂,X已知X²+3X+1=0,求(1)x+1/x,(2)x²+1/x²+2x+2/x的值前面一个x是多打的 回答下列数学题,要准确率,不要跑堂,求不等式x-1/6≤x+1/3-x-1/2的非负整数解 回答下列数学题,要准确率,不要跑堂,直角三角形的最长边长为13,最短边长为5,则这个三角形的面积为A65/2 B30 C78 D无法计算 回答如面的英语题,不要跑堂,要准确率,()的意思是补充什么单词,mary often s() two hours reading stories every dayjane is very p() of her new carare you p() about the results she was s() at us in a friendly wayI want to i() our fr 回答下列英语题,要准确率,不要跑堂,将下列句子合并为含有宾语从句的复合句.1.was,better,our,team,i,think(.)2.free tomorrow ,lily says,won't,she,be(.)3.father christmas isn't real ,the children didn't know(.)4.''the stati 回答下列英语题,要准确率,不要跑堂,括号代表填入单词,急,1.The medicine tasted b() and the child spat it out 2.He was so n() about his exams that he couldn't sleep3.How did you do on your maths t()?4.We started our journey in high 回答下列英语题,要准确率,不要跑堂,括号代表所填单词一:1.Tom lost his bike .he felt s()2.The teacher a() his suggestions3.There are four important r() in Beijing Opera4.My father always makes me l()5.Don't w() about your mother 用所给词的适当形式填空,要准确率,不要跑堂,---代表所填的词的适当形式1.it's better---(get) some food before they start .2.they had a ---(wonder) train ride to sichuan .3.the ---(many) trees,the better.4.what's the ---(dif 扬州个园 阅读答案,要准确率,不要跑堂,急求,谢谢扬州个园①江苏的苏州个园,是一座独具风格的名园.它是清嘉庆、道光年间两淮盐总黄至筠在明代寿芝园旧址上兴建起来的.当时园中遍植翠 秋天阅读答案,要准确率,不要跑堂,急求,谢谢了震落了清晨满披着的露珠,   伐木声丁丁地飘出幽谷.   放下饱食过稻香的镰刀,   用背篓来装竹篱间肥硕 的瓜果.   秋天栖息在农家里 用所给词的适当形式填空.要准确率,不要跑堂,---代表所填的词1.on a rainy day,you mustn't drive ---(quick)2.pay attention to traffic ---(light).3.go ---(cross) the street,you can find the bookshop .4.---(travel) on foot is slow 5. 方框填词.(用所给词的适当形式填空)要准确率,不要跑堂,---代表所填的词.,为一个if ,while ,learn,see ,please,so ...that ,pay for,as soon as1.if you have lost the book ,you must ---it 2.the old man was--- hungry --- he co 方框填词.(用其适当的形式)要准确率,不要跑堂,括号代表填入的词upset ,prepare for ,take care of ,look tired ,no longer ,not so clean as ,used to,be afraid to 1,their classroom is ()ours 2.his father () be a policeman 3.mary 用所给词的适当形式填空,要准确率,不要跑堂,,横线代表所填词的形式1:He likes -----(go) to the movies with his friends2:he---(fail) his exam yesterday he was ---(happy)3:Our ---in school are ---(friend) to us4:How many 购买上帝的男孩阅读题答案,要准确率,不要跑堂,购买上帝的男孩一个小男孩捏着1美元硬币,沿街一家一家商店地询问:“请问您这儿有上帝卖吗?”店主要么说没有,要么嫌他在捣乱,不由分说 选择适当的词语,并用其正确形式填空.要准确率,不要跑堂,a expensive/cheap1.the machine is newly invented,so it is very---2.this shirt is ---,but it is as good as the others.i'll buy it.b family/house/ home1.he always stays at ---o 用所给词的适当形式填空,要准确率,不要跑堂,急,1.'---(not be) late for school again ,' mrs li said 2.mary made him ---(wash) the sweater last sunday 3.one of the girls ---(sing) now 4.don't talk ---(loud) in class 5.her mother is goo 用所给词的适当形式填空,要准确率,不要跑堂,1.while he---(stay) there,he went to see his friend .2.we ---(go) to school as soon as the building ---(be) over next week.3.--- (not get) off the bus until it ----(stop)4.how much did you--