1.若(z-x)2-4(x-y)(y-z)=0.求证:x,y,z成等差数列..ps:这里的2是平方..2.在三角形ABC中,若BC=a,CA=b,AB=c,且sin2A,sin2B,sin2C成等差数列,求证:cosA/a,cosB/b,cosC/c也成等差数列..ps:这里的2也是平方..3.已知一等差数

若x,y,z成等差数列,则(z-x)^2-4(x-y)(y-z)= 若x,y,z成等差数列,则(z-x)^2-4(x-y)(y-x)= 1.若3x-2y+z=2;3x+2y+5z=4,求x+22.若x-3y+z=0;3x-3y-4z=0,求x:y:z (x-y)^2+4z(x-y)+4z^2 化简-(-3x-y+2z)-{-x+【4x-(x-y-z)-3x+2z} 若x+y+z=3y=2z,则x/x+y+z=? x+2y=3x+2z=4y+z 求x:y:z x+y/2=z+x/3=y+z/4 x+y+z=27 数学--整式运算4(x-y+z)-2(x+y-z)-3(-x-y-z) (x*x+2)(y*y+4)(z*z+8)=64xyz,求x,y,z 化简(y-x)(z-x)/(x-2y+z)(x+y-2z)+（z-y)(x-y)/(x-2z+y)(y+z-2x)+(x-z)(y-z)/(y+z-2x)(x-2y+z) 计算:(y-x)(z-x)/(x-2y+z)(x+y-2z)+(z-y)(x-y)/(x+y-2z)(y+z-2x)+(x-z)(y-z)/(y+z-2x)(x-2y+z) 若（z-x)的平方-4(x-y)(y-z)=0试确定x-2y+z若（z-x)^2-4(x-y)(y-z)=0试确定x-2y+z 若实数XYZ满足2|x-y|+√2y+z+z方-z+1//4=0 求X+Y+Z 2y+z在根号里 计算:x^2/(x-y)(x-z)+y^2/(y-x)(y-z)+z^2/(z-x)(z-y) 1.（x+y-z)+(x-y+z)-(x-y-z) 2.2x-(3x-2y+3)-(5y-2) 若x:y:z=2:3:4,求x+y+z/x-2y+3z的值 若x/2=y/3=z/4,则3x-2y+5z/x+y+z=