①4(x+y)-5(x-y)=51 5(x+y)-4(y-x)=33 ②2x+4y=2 2x-6y=-2分之1 ③ 6x
{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1
3分之2(X-Y)-4分之X+Y=-1,6(X+Y)-4(2X-Y)=16
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)-4(x-y)=11,2(x-y)+5(x+y)=27
化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1
已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-(
已知x²+y²+5=2x+4y,求【2x²-(x-y)(x-y)】【(x+y-1)(x-y
已知x*x+4x+y*y-2y+5=0,则x*x+y*y=?
方程2分之x+y+2分之x-y=7,4(x+y)-5(x-y)=2
3x+2y/4=2x+y/5=x-y+1/6