knrt.net
当前位置:首页 >> 6x 2 xy 2y 2 2x 8y 8 >>

6x 2 xy 2y 2 2x 8y 8

原式=(2x-y)(3x+2y)+2x-8y-8 2x-y -2 × 3x+2y 4 x系数-6+8=2 y系数-4-4=-8、 原式=(2x-y-2)(3x+2y+4)

6x²+xy-2y²+2x-8y-8=0 (3x+2y)(2x-y)+2x-8y-8=0 (3x+2y+4)(2x-y-2)=0 3x+2y+4=0 2x-y-2=0 解得:x=0 y=-2

双十字相乘

2(3x2-2xy+4y2)-3(2x2-xy+2y2),=6x2-4xy+8y2-(6x2-3xy+6y2),=6x2-4xy+8y2-6x2+3xy-6y2,=-xy+2y2;当x=2,y=-1时,原式=-2×(-1)+2×(-1)2=2+2=4.

/x/=三分之八,/y/=四分之十五,且xy

∵6x2+7xy-3y2=(2x+3y)(3x-y),∴故可设6x2+7xy-3y2-8x+10y+c=(2x+3y+a)(3x-y+b)(其中a、b均为常数).比较两边x、y的系数,得到3a+2b=?8?a+3b=10,解得a=?4b=2,∴c=ab=-4×2=-8.故答案为-8.

原式=[6x3y+6x2y2-3x3y+3x2y2]÷3x2y=(3x3y+9x2y2)÷3x2y=3x3y÷3x2y+9x2y2÷3x2y=x+3y.

6x^2+xy-2y^2=0 (2x-y)(3x+2y)=0 x=y/2 or x= -2y/3 x/y = 1/2 or -2/3

2x(x+2y)²-(2y+x)² =(x+2y)²(2x-1) =(1/2-2/3)²(2*1/2-1) =(1/2-2/3)²*0 =0

6x^2-xy-2y^2-4x+5y-2 =(2x+y-2)(3x-2y+1)

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