5X+4Y=444X+Y=3Y+X 可以得出X=4 Y=6 因为我才上六年级 一定要完整的过程,

已知2x+3y-4z=0,3x+4y+5z=0,求x+y+z/（除以）x-y+z的值.因为我才开始学三元一次,所以有很多 {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 x+y/2+x-y/3=6,4(x+y)-3(x-y)=-20 {(x+y)/2+(x-y)/3=6 4(x+y)-3(x-y)=-20 4(x+y)-3(x-y)=-20,2/x+y+3/x-y=6 ｛4/(x+y)+6/(x-y)=3 ｛9/(x-y)-1/(x+y)=1 （5x+3y)(3y-5x)-(4x-y)(4y+x)= 3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27 {2分之x+y+3分之x-y＝6 4(x+y)-5(x-y)=2方程组的解要有过程 2分之x+y+3分之x-y＝6 4(x+y)-5(x-y)=2方程组的解要有过程 已知x,y满足x²+y²-4x+6y+13=0则(3x+y)²-(3x+y)(3x-y)的 已知XY.Y=-3,求-XY(X.X.X.Y.Y.Y.Y.Y.Y.Y-3.X.X.Y.Y.Y.Y.Y-Y)的值.（过程完