求数学题x=1/2,y=-1/3,求(x+y)²+2(x+y)(x+2y)+(x+2y)²急!
若|x+2y-1|+y²+4y+4=0,求(2x-y)²-2(2x-y)(x+2y)+(x+2y)&
若|x+y-1|+(x-y-2)²=0,求代数式(x+2y)(x-2y)-(2x-y)(-y-2x)的值.
已知:3x=8y.求(1)x+y/y (2)2x+3y/x-2y
(1)已知x+y=6,x²-y²=5,求x-y的值(2)若x+y=3,x²+y²
求因式分解(x-y)²-2(x-y)³和(x+y)(x-y)-x(x-y)
已知x²+|y+x|=x-1/4,求(3x+y)²(2x-y)²-(4x²+y&
2x²-3xy=y²=0(x,y不得o)求x/y+y/x
已知方程组2x+y=6 x-3y=1,求7y(x-3y)²-2(3y-x)³的值
已知x=3分之1,y=二分之一,求代数式x-(x+y)+(x+2y)-(x+3y)+...-(x+13y)的值
已知|x+y+2|+(2x-3y-1)²=0 求 ⑴x、y的值 ⑵2x³-x²-3y
当x=2,y=-1时,求代数式(x+y)(x-y)+(x-y)²-(x²-3xy)的值
【(X²+Y²)-(X-Y)²+2Y(X-Y)】/4Y=1,求4X/4X²-Y&