若x^2-4y^2=-15,2y-x=5,则x+2y=____

若x,y互为相反数（y≠0）,则2x+5+2y+3x/y=____ 若实数x,y满足(x-2y-2)(3x+2y+2)+2(x2+4)=0,则x=____,y=____ 1.若2x-y=0,且x-5＞y,则x、y的取值范围是x=____,y=____. 已知x*x+4x+y*y-2y+5=0,则x*x+y*y=? 已知x ^2+9y ^2-2x+12y+5=0,则x=____,y=____. 若方程|x+y-2|+(x-y-4)的二次方=0,则2x+y=____ 实数x,y满足3x+4y=15,则x^2+y^2的最小值是____ 若(x*x+y*y)(x*x+y*y)-4x*x*y*y=0,求代数式(x*x+5xy+y*y)/(x*x+2xy+y* 已知x²+y²-2x+4y+5=0,则（x+y）2012次方=____. 3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)