X:Y:Z:U=1:2:3:4 9X+7Y+3Z+2U=200是一的方程组

四元一次方程的解法y+z+u=1z+u+x=2u+x+y=3x+y+z=4 X:Y:Z:U=1:2:3:4 9X+7Y+3Z+2U=200是一的方程组 解方程组X:Y:Z:U=1:2:3:4,9X+7Y+3Z+2U=200粗略的过程给下! 三（四）元一次方程组!1.2z-6=-2(x+3y)3(5y+x)=6-7z4(x+z)=9+9y2.2x-5y=-117y+4z=55x+2z=23.0.4x+0.3y-0.2z=40.6x-0.5y+0.3z=50.3x+0.2y+0.5z=224.x/2+3y/4+5z/3=455.1x+6y/5-4z=150.1x-0.4y+4z/5=55.x+y=7y-z=1z+2u=4u-3x=-11 当x,y,z>0时x+2y+3z=1u=x*x/(x+1)+4y*ysup2/(2y+1)+9z*z/(3z+1)的最小值 x大于等于0,y大于等于0,z大于等于0.3x+2y+z=5,2x+y-3z=1,u=3x+y-7z 求u的最值, 已知x/(y+z+u)=y/(z+u+x)=z/(u+x+y)=u/(x+y+z)求(x+y)/(z+u)+(y+z)/(x+u)+(z+u)/(x+y)+(u+x)/(y+z) 设X,Y,Z是相互独立的,N(2,4),E(2),U(-1,2),若W=2X+3XYZ-Z+5,U=3X-2Y-Z+4,求E(W)和D(U)? ..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 f(x,y,z,w)=x*(x+y)*(x+y+z)*(x+y+z+w)f=x+1, u=x+2, z=x+3, c=x+5, v=x+6, k=x+7, l=x+8求f(f,u,c,k) 解下列三元一次方程组:(1)x-z=4,x+y-z=-1,2y-z=1 (2)3x+4z=7,2x+3y+z=9,x-y+z=8 设x+y+z=11求函数u=2x*x+3y*y+z*z的最小值 六年级三元一次方程组.解下列方程组：(1)5x-3y+z=25x+2y-4z=3-5x+y-z=2(2)x-y-z=-13x_5y+7z=114x-y+2z=-1(3)9x-5y+z=-69x+y+4z=3-9x+3y-5z=0(4)x+y=22x+z=-27y+z=13 x/(y+z+u)=y/(z+u+x)=z/(u+y+x)=u(x+y+z)求(x+y)/(z+u)+(y+z)/(y+x)+(z+y)/(x+y)+(u+x)/(z+y) 已知int x=1,y=2,z=3;boolean u=true指出以下表达式结果u=y>z^x!=z为什么? 已知x y满足x-y≥2,2x+3y≥9,x≤4 ,求z=10x+10y最大值 u=(y+1)/(x-2)范围 已知x,y,z都不小于0,且满足3y+2z=3-x,3y+z=4-3x,若u=3x-2y+4z,求u的最大值求!谢谢了! 已知x,y,z都不小于0,且满足3y+2z=3-x,3y+z=4-3x,若u=3x-2y+4z,求u的最大值 和最小值