已知xy是方程组①x+2y=4②x-y=-5的解,求1-x-y/x+2y÷x²-y²/x²
已知x-5y=0,求分式x²-2xy+y²/3x+y × (y-x)的值
已知x/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y²
已知x+y=1,xy=-2分之1,利用因式分解求:x(x+y)(x-y)-x(x+y)²的值
已知:(x+2)²+|x+y-10|=0,求3x²y-[5x²y-﹙2xy-x²
已知x-y=1,y≠0,求{(x+2y)²+(2x+y)(x+4y)-3(x+y)(x-y)}÷y的值.
已知x,y的值满足方程组x+2y=3,x-y=-2,求x/(x-y)²+x²-y²/(x+
已知x²+y²-2x+4y+5=0,求X^4-y^4/2x^2+xy-y²·2x-y/xy
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=1,xy=-2,求(3x-4y+2xy)-(2x-5y+5xy)的值
已知:x-y=1,xy=-2,求(3x-4y 2xy)-(2x-5y 5xy)的值
已知x²+y²+5=2x+4y,求【2x²-(x-y)(x-y)】【(x+y-1)(x-y
1、已知实数x、x满足x²+y²-xy+2x-y+1=0,试求x、y的值.