已知2^x = 8^y+1,9^y = 3^x-9 ,1/3x+1/2y =

已知4x=9y求(1)x+y/y (2)y-x/2x 已知：3x=8y.求（1）x+y/y (2)2x+3y/x-2y 9y=3x-(x-1),4(x+y)-(2x+4)=8y 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2^x = 8^y+1,9^y = 3^x-9 ,1/3x+1/2y = 已知x=2+根号3,y=2-根号3,计算代数式(x+y/x-y-x-y/x+y)乘以(1/x^2-1/y^2) 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 已知x,y满足（2X+3y+1)^2+/4x-9y-8/=0.求x,y的值. 已知x,y满足（2x+3y+1)的平方+|4x-9y-8|=0.求x,y的值 (1/2)已知实数x,y,a满足：根号(x+y-8)+根号(8-x-y)=根号(3x-y-a)+根号(x-2y+a+3) 已知X-Y=3,求X-Y的2次幂减3X+3Y+1 已知|2x-3y|+|3x-y-1|=0,求x,y的值.