x：y=5:3①{ x：z=7:3②2x-y-z=34③注意是三元一次方程

①5x-4y+4z=132x+7y-3z=193x+2y-z=18②y=2x-75x+3y+2z=23x-4z=4 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 解三元一次方程 快①｛2x+y+z=15 ②｛2x+y=3 ③｛x:y=5:3 ④｛x/2=y/3=z/4x+2y+z=16 3x-z=7 x:z=7:2 3x-2y+5z=20x+y+2z=17 x-y+3z=0 x-2y+3z=92 x+y-z=3 y+z-x=5 z+x-y=7 求x,y,z x/2=y/3=z/5 x+3y-z/x-3y+z 已知x/2=y/4=z/7,求①x：y：z.②若2x+y+3z=58,分别求x,y,z的值.③求x+y/x+z的值. ①3x-4y+z=14x+5y+2z=172x+2y-z=3② x:y=3:2y:z=5:4x+y+z=66 x/5=y/3 x/7=z/3 2x-y-z=34 解三元一次方程,①{x+y-z=0{ x+2y+z=13{2x-3y+2z=5②｛x+y-z=11｛y+z-x=5｛z+x-y=1③｛x+y=1｛y+z=6｛z+x=3 已知x-y/x+y=y+z/2(y-z)=z+x/3(z-x),求证8x+9y+5z=0THX.. 若X:Y:Z=5:6:7那么(Y-X):(Y+Z)和(X+2Y+3Z):(3X+2Y+Z) x+Y+Z=1 X+3Y+7Z=-1 X+5Y+8Z=2x+Y+Z=1X+3Y+7Z=-1X+5Y+8Z=2 ①x+y+z=6 3x-y+2z=12 x-y-3z=-4 ②x+y-z=2 4x-2y+3y+8=0 x+3y-2z-6=0③x/3=y/2 y/4=z/5 x+y+z=60三元一次方程 2x+4y+3z=9① 3x-2y+5z=11② 5x-6y+7z=13③ 2x+4y-3z=9① 3x-2y-4z=8② 5x-6y-5z=7③ {5x-3y+z=2{5x+2y-4z=3{-5x+y-z=2 {x-y-z=-1{3x+5y+7z{4x-y+2x=-1 已知(x+y)(x+z)=x,(y+z)(y+x)=2y,(z+x)(z+y)=3z,求x,y,z 试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y)