如果x+y=9,x2-y2=27,则x-y=___.
若x-y=2,x2-y2=10,则x+y= ___ .
如果x,y满足4x2+9y2=36,则|2x-3y-12|的最大值为___.
已知正实数x,y满足x2+y2+xy=1,则x+y的最大值是___.
若点P(x,y)满足x2+y2=25,则x+y的最大值是 ⊙ ___ .
若x+y=12,求x2+4+y2+9的最小值___.
若x2+y2=1,则3x-4y的最大值是___.
如果x+y=-1,x-y=-3,那么x2-y2=______.
计算:(x2-2x+1-y2)÷(x+y-1)= ___ .
已知实数x,y满足方程(x2+2x+3)(3y2+2y+1)=43,则x+y= ___ .
已知实数x,y满足x2+4xy+4y2-x-2y+14=0,则x+2y的值为 ___ .
我做对了吗.x2(x-y)+y2(y-x)= x2(x-y)-y2(x-y)=x2-y2=(x+y)(x-y)
已知x2+4x+y2-2y+5=0,则x2+y2=______.