若(x+y)2=25,(x-y)2=1,x2+y2的值是______.
若(x+y)2=25,(x-y)2=1,x2+y2的值是______.
(选做题)已知x+2y=1,则x2+y2的最小值是______.
已知实数x、y满足(x2+y2)(x2+y2-1)=2,则x2+y2的值为______.
已知x-y+1,X2+Y2=25 求(x+y)2和x2-xy+y2的值
已知x-y=5,(x+y)2=49,则x2+y2的值等于______.
若实数x,y满足2x2+3y2=1,S=3x2-2y2,则S的取值范围是______.
已知实数x.y满足(x2+y2)(x2+y2-1)=2,求x2+y2的值
若|2x+y-1|+(x-2y)2=0,则x2+xy+y2的值为______.
若x2-y2=100,x+y=-25,则x-y的值是( )
若实数x,y满足3x2+2y2=6x,则x2+y2的最大值为______.
已知2x+y=7,x2+y2=5,求(4x+2y)2-3x2-y2+2(1-y2)的值.
若x2+2xy+y2-a(x+y)+25是完全平方式,则a=______.