填空：①x(y-z)-y(z-y)= ②（x-1)(x-2)-2乘(2-x)的平方= ③2乘x的平方-4x+2= ④x的平方-4x=

(x-y-z)*( )=x^2-(y+z)^2 填空 填空a(x+y-z)+b(x+y-z)-c(x+y-z)=(x+y-z)乘以() (x+y-z)(x-y+z)= 填空x+y-z=x+( )=x-( )填空x+y-z=x+()=x-() X+Y+Z=? x/y=(x+z)/(y+z)y/z=(x+y)/(x+z) 2y+z=3y ① ,x+3y-z=8,② x+y+2z=13③ 求x,y,z 已知 x/(y+z)+y/(z+x)+z/(x+y)=1求 (x*x)/(y+z)+(y*y)/(x+z)+(z*z)/(x+y)=? 解方程组x+y/2=z+x/3=y+z/4①x+y+z=27② (y+z)/x=(z+x)/y=(x+y)/z求x+y-z/x+y+z的值 已知4x-3y-3z=0,① x-3y+z=0,②并且z不等于0,求x：z与y：z 解三元一次方程组 ①2x-y+z=1 3x+y -2z=2 X+2y-z=3 ②x-4y+z=-3 2x+Y-Z=18 X-Y-Z=7 ③4x+4y+2z=7 6X-4y-z=6 2x-y+z=1 x=y; y=z; z=x/y fangchengzu:X+Z=Y 7Z=X+Y+Z X+Y+Z=14 用行列式的性质证明：y+z z+x x+y x y z x+y y+z z+x =2 z x y z+x x+y y+z y z x 这个怎么证? (x-2y+z)(x+y-2z)分之（y-x)(z-x) + (x+y-2z)(y+z-2x)分之(z-y)(x-y) + (y+z-2z)(x-2y+z)分之（x-z)(y-z)=?第三部分那个是 （y+z-2x)(x-2y+z)分之（x-z)(y-z) ①3x-4y+z=14x+5y+2z=172x+2y-z=3② x:y=3:2y:z=5:4x+y+z=66 填空：（x-y-z）（_________）=x^2-（y+z）^2