z=1/2-(5/2)X^2x^2 怎么弄...

｛x-z=-1 2x+y+3z=5 x +y-z=1 怎么解, (X+Z)(X-Z)+x(X+2Y)怎么解? x-z=-4 z-2y=-1 x+y-z=-1 怎么解 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+y=5,y+z=-1,z+x=-2怎么算 {x:y:z=3:4:5 {x+2y+z=48 怎么解 (x-2y+z)(-x+2y+z)怎么解? 三元一次方程组： z=x+y (1) 3x-2y-2z=-5 (2) 2x+y-z=3 (3) 怎么解 三元一次方程2x+3y+z=6 x-y+2z=-1 x+2y-z=5 怎么解 怎么做3元一次方程2x+3y+z=6x-y+2z=1x+2y-z=5 三元一次方程x+4y+3z=1 2x+5y+4z=4 x-3y-2z=5怎么解 三元一次方程组y-3x-2z=1 x+2y+3z=9 5x-7y+z=34怎么解 X-7Y+3Z=17和5X-6Y-Z=24和3X+7Y-2Z=1怎么解? x+2z=3 2y+z=7 2x-y-z=-5怎么解? 化简:(2x-y-z)/(x-y)(x-z)+(2y-z-x)/(y-z)(y-x)+(2z-x-y)/(z-x)(z-y)化简:(2x-y-z)/(x-y)(x-z)+(2y-z-x)/(y-z)(y-x)+(2z-x-y)/(z-x)(z-y)我知道把分母化成一样的、但是之后怎么算? 语句{intx,y,z ;x=1,y=z=2; ++x&&y--||++z}怎么理解 x/2=y/3=z/5 x+3y-z/x-3y+z {x+y+z=1;x+3y+7z=-1;z+5y+8z=-2