设x=25 y=15求代数式 ：√x³-x²y+1/4y² - √1/4x³-x

设x-2的绝对值+(y+1/4)平方=0,试求代数式x²（x²-xy+y)-x(x³-2x 已知x²+y²+5=2x+4y,求代数式（2x²-（x+y)(x-y))x((x+y-1) 4/X+1/Y=2,XY=-1,求代数式4Y-X/X-2Y/（x+2y-12Y²/x-2y)的值 已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-( 设|X-2|+(Y+1/4)^2=0,试求代数式X^2(X^2-XY+Y)-X(X^3-2X^2Y+XY-1) 当x=1/2,y=1/3时,求代数式-(x²+4y)-(x³-3y+2）+2(x³+1/2 若|x+y-1|+（x-y-2)²=0,求代数式（x+2y)(x-2y）-（2x-y)(-y-2x)的值. 设x=1/√3-2,y=1/√3+2,求代数式x²+xy+y²/x+y的值 x(x-2)-(x²-2y)=-4求代数式1/2(x²+y²)-xy的值... 若x-y=1,求代数式x(x-y)+y(y-x)+2013的值 已知x²+y²+5=2x+4y,求【2x²-(x-y)(x-y)】【(x+y-1)(x-y 已知x²-4x-1=0,求代数式(2x-3)²-(x+y)(x-y)-y²求大神帮忙