4x+8(x+y)=480 4y+9(x+y)=480
9y=3x-(x-1),4(x+y)-(2x+4)=8y
已知x²+y²-8x+6y+25=0,求(x-y+4xy/x-y)(x+y-4xy/x+y)
{4/(x+y)+6/(x-y)=3 {9/(x-y)-1/(x+y)=1
已知4x=9y求(1)x+y/y (2)y-x/2x
[(x+2y)(x-2y)-(x-2y)^2+8y(x+y)]除以4x=
(4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai
【(2x+y)²-y(y+4x)-8x】÷2x,其中x=100
若|x+2y-1|+y²+4y+4=0,求(2x-y)²-2(2x-y)(x+2y)+(x+2y)&
已知2x-y=8,求{(x的平方+y的平方)-(x的平方-y的平方)+2y(x-y)}除4y
已知X.x+y.y-4x+2y+5=0,求4X.X-12X Y+9Y.y的值
已知x的平方+y的平方-8x+6y+25=0,求(x-y+4xy/x-y)(x+y-4xy/x+y)
已知实数x.y满足根号(x+y-8)+根号(8-x-y)=根号(3x-y-4)+根号(x-2y+7),求x,y