若x+2y=1,2x-3y=2,则2x+4y-6/2+6x-9y/4=?
{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
若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于
若2x-3y+4=0则x(x*x-1)+x(5-x*x)-6y+7
若5x+3y=3x+4y=x+2y+6,则x+y=___
已知4x=9y求(1)x+y/y (2)y-x/2x
【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2=
9y=3x-(x-1),4(x+y)-(2x+4)=8y
化简求值:(7x-2y)(3x-2y-1)-(4x+3y)(9x+6y),其中x=2,y=-1
若实数X,Y满足X²+Y²+4X-2Y +1=0,则X²-6X+Y²-2Y的最大