已知y=-1/2x^2+7x+15/2
已知4x=9y求(1)x+y/y (2)y-x/2x
已知X和Y满足3X+4Y=2,X-Y-1/7
已知x,y满足约束条件:x-y+1>=0,x+y-2>=0,x
已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-(
已知x²+y²+5=2x+4y,求【2x²-(x-y)(x-y)】【(x+y-1)(x-y
已知X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/X+Y
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
已知x>-1,求函数y=(x^2+7x+10)/(x+1)的最小值
已知1/x-1/y=3,则代数式x(2-7y)-y(7x+2)/x(1-y)-y(x+1)的值为多少.
已知:3x=8y.求(1)x+y/y (2)2x+3y/x-2y
已知有理数x,y满足1/2|x-y|+|y-1/2|=0 求3x+7y
已知:x,y满足|2x-y|+|y-1/2|=0,求7x-3y的值.