注意,1)(2a-5b)(2a-5b+4)-212)-4yz+3x^2-2xz+6xy
若实数xyz满足(x-2y+z)^2+4(x-y)(y-z)=0 A xy-yz=0 B xy+yz=0 C xy-xz
若x/2=1/y=z/3,且xy+xz+yz=99,求4x^2-2xz+3yz-9y^2的值.
因式分解x^2-xy+xz-yz
已知:xy/(x+y)=a,xz/(x+z)=b,yz/(y+z)=c,且abc不等于0,求证:x=2abc/(bc+a
已知:xy/(x+y)=a,xz/(x+z)=b,yz/(y+z)=c,且abc不等于0,求证:x=2abc/(bc+a
(2X+Z-Y)/(X^2-XY+XZ-YZ)-(Y-Z)/(X^2-XY-XZ+YZ)
yz/(bz+cy)=xz/(cx+az)=xy/(ay+bx)=(x^2+y^2+z^2)/(a^2+b^2+c^2)
如果xy=a,xz=b,yz=c,abc≠0,那么x^2+y^2+z^2=______
解方程组(x+y)/xy=5/6,(y+z)/yz=-2/3,2(x+3)+xz=0
张华在一次测验中计算一个多项式加上5xy一3yz+2xz时,误认为减去此式,计算出错误结果为2xy+6yz-4xz
设x,y,z∈R+,xy+yz+xz=1,证明不等式:(xy)^2/z+(xz)^2/y+(yz)^2/x+6xyz≥x
x^2+y^2+xy=25/4,x^2+z^2+xz=169/4,y^2+z^2+yz=36,求xy+xz+yz