4（x+y)-(x-3y)=4 3/x+2/y=1

(x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= （y-x)+x(x-y)^3-(y-x)^4 因式分解 计算 3x+4y/x-y+3y/y-x-4x/x-y 3x+4y/x-y +3y/y-x -4x/x-y x(4y-x)(x-3y)+y(3y-x)(x-4y)因式分解 （3x-y)(y+3x)-(4x-3y)（4x+3y)=? {3(x+y)+3(y+x)=1,3(x+y)+4(y-x)=-1 2（x+y)-3(x-y)=3 ,4(x+y)+3(x-y)=15 （5x+3y)(3y-5x)-(4x-y)(4y+x)= {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 3(x+y)-2(x-y)=11 4(x+y)+3(x-y)=9 x(x-3y)=4y(x-3y),求x:y 4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11 3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27 3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2