已知、5x²-2xy+y²+4x=1=0求[(x+y)(x-y)-(x-y)²+2y(x-3y)]÷(-4y)的值
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/12 20:39:03
![已知、5x²-2xy+y²+4x=1=0求[(x+y)(x-y)-(x-y)²+2y(x-3y)]÷(-4y)的值](/uploads/image/z/2681833-49-3.jpg?t=%E5%B7%B2%E7%9F%A5%E3%80%815x%26sup2%3B-2xy%2By%26sup2%3B%2B4x%3D1%3D0%E6%B1%82%5B%28x%2By%29%28x-y%29-%28x-y%29%26sup2%3B%2B2y%28x-3y%29%5D%C3%B7%28-4y%29%E7%9A%84%E5%80%BC)
xQKN0
JHL\7s"*${>BˊOT@T|M 8
vBVc.PŦ5h\>z)JZZPֹa0_Au QTizr?sv9[,rjCl26:J;PU*5?KuPDh]v_,Yr_ɃKUSWr,9Ƀ⡽"g1KBR|(CHB0hXȤN$H12PU;i)UZ涫HP\XGy>8v~"E2ɛ+
已知、5x²-2xy+y²+4x=1=0求[(x+y)(x-y)-(x-y)²+2y(x-3y)]÷(-4y)的值
已知、5x²-2xy+y²+4x=1=0求[(x+y)(x-y)-(x-y)²+2y(x-3y)]÷(-4y)的值
已知、5x²-2xy+y²+4x=1=0求[(x+y)(x-y)-(x-y)²+2y(x-3y)]÷(-4y)的值
(x²-2xy+y²)+(4x²+4x+1)=0
(x-y)²+(2x+1)²=0
平方大于等于0,相加等于0,若有一个大于0,则另一个小于0,不成立.
所以两个都等于0
所以x-y=0,2x+1=0
x=-1/2,y=x=-1/2
[(x+y)(x-y)-(x-y)²+2y(x-3y)]÷(-4y)
=[(x+y)*0-0²+2y(x-3y)]÷(-4y)
=-(x-3y)/2
=-(-1/2+3/2)/2
=-1/2
题目有问题:5x²-2xy+y²+4x=1=0,怎么会有1=0????