28\x+30\z+35\y=4.5 28\y+30\z+35\x=4.3 x+y+z=142 帮我解.马上!那个4.3改为4.7

x/30+y/28+z/35=4.5 x/30+y/35+z/28=4.7 x+y+z=142 这个方程怎么解?详细过程 x+y+z=142 x/28+y/30+z/35=4.5 z/28+y/30+x/35=4.7 怎么解. 一道三元一次方程六年级的速度!x/28+y/35+z/30=4.5 ｛x/35+y/28+z/30=4.7 x+y+z=142 解方程组：x/28+y/35+z/30=4.5①；x/35+y/28+z/30②；x+y+z=142③ x+y+z=35 2x-y=5 y/3=z/2 求x,y,z 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) 解方程 x+y+z=0 4x+2y+z=3 9x-3y+z=28解方程x+y+z=04x+2y+z=39x-3y+z=28 试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y) 帮个忙解一下方程2x+2y-z=6x-2y+4z=35x-7y+z=28 已知(x+y)(x+z)=x,(y+z)(y+x)=2y,(z+x)(z+y)=3z,求x,y,z 已知：x^2/(z+y)+y^2/(x+z)+z^2/(x+y)=0,求x/(z+y)+y/(x+z)+z/(x+y)的值. x^2/(z+y)+y^2/(x+z)+z^2/(x+y)=0,求x/(z+y)+y/(x+z)+z/(x+y)的值 x*(y-Z)=27,y*(x-Z)=35,Z*(x+y)=28三个方程正整数解 方程组{x+y+z=14 3x+2y+z=30 60x+42y+35z=657} X+Y+Z=14 3X+2Y+Z=30 60X+42Y+35Z=657 三元一次方程 3x+7y+4z=35,x+5y+2z=40,x+y+z=( ) 求解三元一次方程组,x+y+z=142 x/30+y/28+z/35=4.5求解三元一次方程组,x+y+z=142x/30+y/28+z/35=4.5x/30+z/28+y/35=4.7