(1)2y-1/2=1/2y-3 (2)-2x=3x+8 (3)56=3x+36-2x (4)3x
已知:3x=8y.求(1)x+y/y (2)2x+3y/x-2y
x(x-1)-(x平方-y)=-3,求x平方+y平方-2xy
{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1
已知x/2=y/3=z/4,求下列各式 (1)(x+y+z)/x (2)(x-y+2x/(x-y-2z)
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x²+|y+x|=x-1/4,求(3x+y)²(2x-y)²-(4x²+y&
9y=3x-(x-1),4(x+y)-(2x+4)=8y
先化简再求值(x-y)(x+y)-(x-2y) 的完全平方+x(3x-5y)-(x-y)(x-2y),其中x=1/2 y
化简求值8x的平方-5x(4y-x)+4x ×(-4x+5/2y)x=1 y=3
函数,y=3x/(x^2+x+1) ,x
函数y=3x/(x^2+x+1) (x
10/x+y+3/x-y=-5 15/x+y-2/x-y=-1(用换元法解此方程组)