3x-4y=18 ;6y-z=-19 ;2x-3y+4z=17 .

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 ｛3X-4y=18 ,｛6Y-Z=-19,｛2X-3Y+4Z=17 3x-4y=18 ;6y-z=-19 ;2x-3y+4z=17 . 方程题4道1.4(x-y-1)=3(1-y)+3.5 (x/2)+(y/3)=2 2.2(x-y)/3-(x+y)/4=13/6 6(x+y)-4(2x-y)=16 3.3x-y+z=3 2x+y-3z=9 x+y+z=12 4.5x-4y+4z=13 2x+7y-3z=19 3x+2y-z=18 ..1.x+y+z=26,2.4y+3z=7,y-z=1,3x+2z=17,x+2y-z=18 9x-7y=173.x-7y+3z=17 4.2x+4y+3z=95x-6y-z=24 3x-2y+5z=113x+7y-2z=1 5x-6y+7z=131.x+y+z=26,y-z=1x+2y-z=18 2.4y+3z=7,3x+2z=11,9x-7y=17 3.x-7y+3z=17 5x-6y-z=24 3x+7y-2z=14.2x+4y+3z=93x-2y+5z=11 5x-6y+7z=13 问5道3元一次方程组题目(1） y=2x-7{ 5x+3y+2z=23x-4z=4 (2) 4x+9y=12{3y-2z=17x+5z=19/4(3）4x-9z=17{3x+y+5z=18x+2y+3z=2(4) 2x+4y+3z=9{3x-2y+5z=115x-6y+7z=13(5) x:y=3:2{y:z=5:4x+y+z=66 已知3X=4X,5Y=6Z求X+Y：Y+Z 3Q一定要有过程.1】 x-2y= ─9 2】3x-y+z=4 3】y=2x-7 4】4x+9x=12 y-z=3 2x+3y-z=12 5x+3y+2z=2 3y-2z=1 2z+x=47 x+y+z=6 3x-4z=4 7x+5z=4/19 4】x：y=3：2 5】x+y+z=26 6】x+y=3 7】x-y-z=2 y：z=5：4 x-y=1 y+z=5 y-z-x= ─5 x+y+z=66 2x-y+z=18 3x-y+z=4,2z+3y-z=12,x+y+z=6的解 解方程组6x=4y=3z,x+y+z=18 解方程 x(x+y+z)=6 y(x+y+z)=12 z(x+y+z)=18 解方程组{x(x+y+z)=6,y(x+y+z)=12,z(x+y+z)=18 X+2Y+3Z=18 X+4Y+3Z=24 Y=? X:Y=3:4,Y:Z=6:5=X:Y:Z=( ):( ):( ) x/6=y/4=z/3,则(x+3y)/(3y-2z) x-4y+z=-302x+y-z=18x--y-z=7 x+y/2=z+x/3=y+z/4 x+y+z=27 x+2y=3x+2z=4y+z 求x:y:z