3x-5y=1(1),4x+6y-7z=2(2),3x-5y+2z=4(3)

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 ..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 (1)2X+4Y+3Z=93X-2Y+5Z=115X-6Y+7Z=13(2)X:Y=3:2Y:Z=5:4X+Y+Z=66(3)3X-Y+Z=32X+Y-3Z=11X+Y+Z=13以上3个题目为三元一次方程~ 4X+3Y-2Z=-7,5X-6Y+Z=1,2X+Z=-2 4X+3Y-2Z=-7,5X-6Y+Z=1,2X+Z=-2 方程组3x+y-4z=1 2x-y-2z=6 5x+3y-3z= --1/2{负二分之一} x=?y=?z=?3x+2y+z=13 x+y+2z=7 2x+3y-z=12 x=?y=?z=? x-y+z=-1 5x+2y-z=6 4x-3y+2z=-5 {x+y+z=1 {x+3y+7z=2 {x+5y+19z=4 x+y+z=1 4x+5y-z=6 x+2y-z=3 {5x-3y+z=2{5x+2y-4z=3{-5x+y-z=2 {x-y-z=-1{3x+5y+7z{4x-y+2x=-1 x-y-z=-1 3x+5y+7z=11 4x-y+2z=-1 分别求出x=?y=?z=? 三元一次方程 X-y-z=-1 3x+5y+7z=11 4x-y+2z=-1 X=?Y=?Z=? 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 已知x:：y：z=3：4：5,(1)求x+y分之z的值；（2）若x+y+z=6,求x,y,z. 1.3(x+y)-4(x-y)=4 x+y/2 + x-y/6 =6 2.x+2y+3z=7 2x+y+z=7 3x+y+2z=11 3.x:y:z=1:2:7 2x-y+3z=214.4x-3y=1 x+2y-z=5 3x-y+2z=2 化简求值4x-{2x+3[x+2(4z-x)-2y]-7y}+6z其中x-y=-3,y-z=-1 解下面三元一次方程组9x-5y+z=5 9x+y+4x=14 -9x+3y-5z=-11 3x-5y+2z=14x+5y-z=5x-5y+3z=-24x+3y-2z=-7 5x-6y+z=-2 2x+z=-2 5x-3y+6z=-3 2x-y+3z=0 y+3z=6 3x+2y 2x+y x-y+1 ----- - ---- = ----- 4 5 6 已知x:y:z=4:5:7,求:(1)2x+3y+z/5z; (2)x+y/y+z.