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

x+x+x+y=60 .x-y=4 (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= 7x:4y,x:y=( ):( (x-4y)(2x+y)= 5x-4y(y-x)=? x(x-y)+4(y-x)因式分解 y=x+4/x (x y=|-x.x+4x+5| (x+y)(x-y)+4(y-1) 4x方y/(x-2y)(x+2y)怎么算[x方/x-2y]-4x方y/(x-2y)(x+2y)=? （y-x)+x(x-y)^3-(y-x)^4 因式分解 {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 （5x+3y)(3y-5x)-(4x-y)(4y+x)= （3x-y)(y+3x)-(4x-3y)（4x+3y)=? (x+y)^2(x-y)^2(x^4+x^2y^2+y^4)=? 化简:(x+y-4xy/x+y)*(x-y-4xy/x-y)= x*x+2x+y*y-4y+5=0 x= y= 如果|X|=4 |Y|=2 且|X+Y|=X+Y 求X+Y