{ 4x+3y=10 x+4y=9

｛4/(x+y)+6/(x-y)=3 ｛9/(x-y)-1/(x+y)=1 (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai 9y=3x-(x-1),4(x+y)-(2x+4)=8y 二元一次方程：{3X=2Y,3X+4Y=36 {3X+4Y=10,4X+Y=9 {2X-Y=6,X+2Y=-2 {X+Y {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 {3(x+y)+3(y+x)=1,3(x+y)+4(y-x)=-1 （5x+3y)(3y-5x)-(4x-y)(4y+x)= 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 已知4x=9y求(1)x+y/y (2)y-x/2x 3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27