{3x+4y=10 5x-6y=4
(4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai
已知X,Y,满足(X+3Y)(X-3Y)=-10(Y^2-6/5)和2X(Y-1)+4(1/2X-1)=0
{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=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
{4/(x+y)+6/(x-y)=3 {9/(x-y)-1/(x+y)=1
3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27
2X+Y+Z=10,X+2Y+Z=-6,X+Y+2Z=8 5X+4Y-3Y=13,2X-3Y+7Z=19,3X-Y=2X
4x-2y-6y*-y-3x+5y* *=2 就是平方
若5x+3y=3x+4y=x+2y+6,则x+y=___