已知x+y=9,xy=10,求x^2+y^2,x^3+y^3,x^4+y^4
已知3x^2+xy-2y^2=0,求{(x+y)/(x-y)+4xy/(y^2-x^2)}/{(x+3y)*(x-y)}
已知x,y>0 2x+y+3=xy 求5x+4y最小值
已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值?
已知x-y=4xy,求x-2xy-y分之2x+3xy-2y的值!
已知x/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y²
已知x-y=3,xy=1,求(-2x+2x+3y)-(3xy+2y-2x)-(x+4y+xy)
已知(x+2)^2+|x+y+5|=0,求3x^2y-[2x^2y-(2xy-x^2y)-4x^2]-xy
已知(x+2)^2+|x+y+5|=0,求3x^2y+{-2X^2y-[-2xy+(x^2y-4x^2)]-xy}
已知:x-y=1,xy=-2.求:(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值
.已知:x-y=1,xy=-2.求:(-2xy+2 x+3y)-(3xy+2y-2x)-(x+4y+xy)的值
已知x^2+3xy-4y^2=0(y≠0),求x-y/x+y的值.
已知:3x方+xy-2y方=0,求(x+y/x-y + 4xy/y方-x方)除以 x方+2xy-3y方 / x方-9y方