2X+Y=10 4Y+Z=21 5X-Z=10

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2X+Y=10 4Y+Z=21 5X-Z=10
求x,y,z的结果!

{2X+Y=10 (1)
{4Y+Z=21 (2)
{5X-Z=10 (3)
（2）+（3）得4Y+5X=31 (4)
由（1）得Y=10-2X (5)
把（5）代入（4）得4（10-2X)+5X=31 -8X+5X=31-40 -3X=-9 X=3
把X=3代入（5）得Y=10-2X=10-2×3=4
把Y=4代入（2）得16+Z=21 Z=5
∴X=3 Y=4 Z=5

(4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai {2x+3y-4z=-5 x+y+z=6 x-y+3z=10 若4x-3y-6z=0,x+2y-7z=0,求代数式5x*5x+2y*2y-z*z/2x*2x-3y*3y-10z*10 2X+Y+Z=10,X+2Y+Z=-6,X+Y+2Z=8 5X+4Y-3Y=13,2X-3Y+7Z=19,3X-Y=2X x+2y+3z=10,x-y+4z=10,x+3y+2z=2 x-y+4z=10,x+3y+2z=2,x+2y+3z=11. x+y+z=4 2x+3y-z=6 3x+2y+2z=10 3x+2y+z=14 ,x+y+z=10,z+2x+3y=1 5 3x+7y+z=5 ,4x+10y+z=6 ,x+y+z= 若3x+7y+z=5,4x+10y+z=3,则x+y+z=? {5X+Y+Z①X+5Y+Z=-2②X+Y+5Z=10③ (x-2y+z)/9=(2x+y+3z)/10=-(3x+2y-4z)/3=1 连等,求x,y,z,