1.当x=3/5,y=-2/5,z=-4/15时,分别求出下列代数式的值：(1) x-(-y)+(-z)(2) x+(-y)-(+z)为什么会这样做,看得懂,还有符号怎么变,)2.已知|x-1|=3,求-3|1+x|-|x|+5的值.(写为什么x会等于…,当x等于…的时候……)3.-|3

已知x+y=3,当y+z=4,x+z=5,则x+y+z等于() C语言if语句和if… else语句技巧当x=3,y=4,z=5时,xyz值分别为多少.1.if（x>z）{x=y;y=z;z=x;} else{x=z;z=y;y=x} x,y,z值 2..if（x>z) x=z; else x=z;z=y;y=x ; x,y,z值 3.if（x!>z) x=z; else x=z;z=y;y=x ; x,y,z值 各自有什么区别? 1.{x:y:z=3:4:5 2x+3y-5z=-142.{x-y-z=-1 3x+5y+7z=11 4x-y+2z=-13.{x+y=1 x+z=0 2x+y+2z=44.{x-y+z=-3 2x-y-z=-2 -3x+y+z=-15.{x-y+z=-3 3x+y-4z=6 2x+y-z=36.{x-2y+5z=16 2x+y-5z=7 2x-y+z=38 三元一次方程组,1.x-2y+z=9 2x+y+3z=10 3x+2y1.x-2y+z=92x+y+3z=103x+2y-z2.3x-5y+2z=14x+5y-z=5X-5y+3z=-23.7x+2y-z=76x-y+z=74x+3y+z=94.4x+3y-2z=-75x-6y+z=12x+z=-25.2x+3y-4z=-23x-2y+5z=262x+5z=31 当x;y;z=1;3;5时,x+3y-z除以x-3y+z等于多少? 三元一次方程解 1.{x+y-z=5 {3x+2y+z=2 {2x-2y+z=-31.{x+y-z=5 2.{9x-5y+x=-6 3.{x-y=3 4.{x+y=3 5.{4x-2y+z=7{3x+2y+z=2 {9x+y-2z=3 {x+z=7 {y+z=4 {2x-y-3z=28{2x-2y+z=-3 {-9x+3y-5z=0 {y-z=6 {z+x=5 {x+y-2z=13 (4x-2y-z)-{5x-[8y-2z-(x-2y)]-x-(3y-10z)}=? 1.已知x:y:z=4:5:7,求：（一）2x+3y+z/5z； （二）x+y/y+z 非常急, 当4x-3y-6z=0,x=2y-7z=0时,求（x方+2y方+5z方）/(x方+3y方+z方）快 ..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 设|x|-|y|+|z|=|x+y+z|,且|x+y|=4,|y+z|=5,|y|=3,求(x-y-z)^2的值 (4x-2y-z)-{5x-[8y-2z-(x+y)]-2(3y-10z)}=?好难啊 x/2=y/3=z/5 x+3y-z/x-3y+z x+y=5 2x+3y-z=9 x-y+z=4 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 已知5x+7y-3z=18,当x=2,y=3时,z= 已知5x+7y-9z=31,当x=2,y=3时,z=_____ 已知：4x-5y+2z=0 x+4y-3z=0则：(x*x+y*y+z*z)/(x*y+y*z+z*x)=____.