若2^x=4^y+1,27=3^x-1,试求x与y的值（过程)

若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 若x=-1/4,能否确定代数式(2x-y)(2x+y)+(2x-y)(y-4x)+2y(y-3x)的值? 若x+y=4,则多项式1/2(x+y)+4(x-y)-3（x-y）-3/2(x+y)-x+y值是（） {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 x+y+2(-x-y+1)=3(1-y-x)-4-(y+x-1),x+y=? 2^x=4^(y-1) 27^y=3^(x+1)求x-y 化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1 先化简 再求值 (2x-y)(y+x)-(x-2y)(2y+x)-(-3y+x)^2其(√x+1)+y^2+4=-4y 已知x-y=1,求[(x+2y)^2+(2x+y)(x-4y)-3(x+y)(x-y)]除以y的值大神们帮帮忙 已知x-y=1,求[(x+2y)²+(2x+y)(x-4y)-3(x+y)(x-y)]÷y的值 若变量x,y满足约束条件{x>=-1;y>=x;3x+2y 9y=3x-(x-1),4(x+y)-(2x+4)=8y 若(-x+6):(x-y):(4x+y)=3:14:1,求x+y 若(-x+6):(x-y):(4x+y)=3:14:1,求x+y 4x(x-y)-(2x-3y)(2x-3y) x=1 y=-1 若x^5+x^4y+x^4+x+y+1=0,且3x+2y=1,求x,y的值 求值域 1,y=(x+2)/(x*x+3x+6) 2,y=3x/(x*x+4)