ppts.net
当前位置:首页>>关于解答题:1.x+y=3,xy=1,求代数式3xy+10y+[5x-(2x...的资料>>

解答题:1.x+y=3,xy=1,求代数式3xy+10y+[5x-(2x...

题目没说清啊,空格处是加号还是减号 如果是+,则答案是-3x^2+7xy+2y^2 如果是-,则答案是-3x^2+7xy-2y^2

(1)∵1x+1y=5,∴x+y=5xy,∴原式=2(x+y)?3xy(x+y)+2xy=10xy?3xy5xy+2xy=7xy7xy=1;(2)∵x2+y2-8x-10y+41=0,∴(x-4)2+(y-5)2=0,∴x=4,y=5,∴原式=(x?y)(x+y)xy=(4?5)(4+5)4×5=-920.

(1)原式=3x2-x2-y2-y2=2x2-2y2;(2)原式=10x-35y-12x+30y=-2x-5y;(3)原式=3x2y-4xy2;(4)原式=3x2y-3xy2-8x2y+12xy2=-5x2y+9xy2.

三个等式解三个未知数,是可以得到唯一解的,但是我想说你这道题目是不是本身就有问题,是不是少打了几个括号啊

2y²-4y+1=0;y=(4±2√2)/4y=(2±√2)/27x(2-x)=3(x-2)²;14x-7x²=3x²-12x+1210x²-26x+12=05x²-13x+6=0(x-2)(5x-3)=0x1=2,x2=3/52x²-3x+3=0判别式=9-24=-15

设这个多项式为Z Z + (2x^2-5xy+4y^2)*2 = x^2-3xy+10y^2 所以: Z =x^2-3xy+10y^2 - (2x^2-5xy+4y^2)*2 =-3x^2 + 10xy + 2y^2 有问题可以追问!如果满意,请采纳为最佳答案。

x^2-4xy+3y^2-4x+10y+3 =(x-y)(x-3y)-4x+10y+3 =(x-y-3)(x-3y-1) x^2+xy-2y^2+2x+7y-3 =(x-y)(x+2y)+2x+7y-3 =(x-y+3)(x+2y-1)

A、∵2x-2y=2(x-y),y-x=-(x-y),∴两个多项式有公因式x-y;B、∵x2-xy=x(x-y),xy-x2=-x(x-y),∴两个多项式有公因式x(x-y);C、3x+y与x+3y没有公因式;D、∵5x+10y=5(x+2y),-2y-x=-(x+2y),∴两个多项式有公因式x+2y.故选C.

网站首页 | 网站地图
All rights reserved Powered by www.ppts.net
copyright ©right 2010-2021。
内容来自网络,如有侵犯请联系客服。zhit325@qq.com