UC知道初一3道数学题目
来源：百度知道 编辑：UC知道 时间：2024/07/03 11:49:40
数学：1.（x²-x+2)(-x-2-x²）
2.（a-2b+3c)(2b-a-3c)
3.(a+b-c-d)(a-b+c-d)
还有英语也帮个忙，首字母填空
One day a man in a restaurant was giving the waiter a lot of reouble.F______ he asked the waiter to turn on the air conditioner b______ he was too hot.Then he asked him to turn it off because he was too cold.This went on for about half an hour.But the waiter was so kind that he did e_______ the man asked him without getting a_____.After that someone else in the restaurant asked w______the waiter did not drive him away."Oh,I do not care,"the waiter said with a s______,"We do not have any air conditioners at all."
能回答多少回答多少啦！！！过了今天作废！！！急死了。。。
2.（a-2b+3c)(2b-a-3c)
3.(a+b-c-d)(a-b+c-d)
还有英语也帮个忙，首字母填空
One day a man in a restaurant was giving the waiter a lot of reouble.F______ he asked the waiter to turn on the air conditioner b______ he was too hot.Then he asked him to turn it off because he was too cold.This went on for about half an hour.But the waiter was so kind that he did e_______ the man asked him without getting a_____.After that someone else in the restaurant asked w______the waiter did not drive him away."Oh,I do not care,"the waiter said with a s______,"We do not have any air conditioners at all."
能回答多少回答多少啦！！！过了今天作废！！！急死了。。。
不知道你要不要过程，我懒得写了，你要是想要的话，再补充问题吧
（1）X^2-(X^2+2)^2= -X^4-3X^2-4
（2）-(a-2b+3c)^2= -a^2-4b^2-9c^2+4ab-6ac+12bc
（3）(a-d)^2-(b-c)^2=a^2+d^2-2ad-b^2-c^2+2bc
First
because
everything
angry
why
smile
数学：1.原式=-(X2-X+2)(X2+X+2)
令X2+2=A,则上式=-(A-X)(A+X)=-(A2-X2)=X2-A2
=X2-(X2+2)2=X2-X4-4X2-4=-X4-3X2-4
2.原式=-(a-2b+3c)(a-2b+3c)=-(a-2b+3c)2
=-[(a-2b)2+6c(a-2b)+9c2]=-[a2-4ab+4b2+6ac-12bc+9c2]
=-a2+4ac-4b2-6ac+12bc-9c2
3.原式=[(a-d)+(b-c)][(a-d)-(b-c)]
令a-d=X,b-c=Y,则上式=[X+Y][X-Y]=X2-Y2
=(a-d)2-(b-c)2=a2-2ad-d2-b2+2bc-c2
注：X2为X平方 X4为X 4次方 同理Y2为Y平方
英语 First because X X why X
数学题 不知道 要干什么
忘了公式，不会做