计算:(2x-y)(4x2+y2)(2x+y)
计算:(x2-2x+1-y2)÷(x+y-1)= ___ .
已知:x2+4x+y2-6y+13=0,求(x-2y)/(x²+y²)
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2x+y=7,x2+y2=5,求(4x+2y)2-3x2-y2+2(1-y2)的值.
已知x,y为实数,且(x2 +y2)(x2 +y2+2)=3.求x2 +y2的值
已知实数x.y满足(x2+y2)(x2+y2-1)=2,求x2+y2的值
(x+3y)2+2(x2-y2)(x2+y2)+(x-3y)2.
已知x2+y2=20,x2+xy-2y2=2(x+2y),求x+y的值
已知x-y+1,X2+Y2=25 求(x+y)2和x2-xy+y2的值
计算:(1)(-7x2-8y2)•(-x2+3y2)=______;(2)(3x-2y)(y-3x)-(2x-y)(3x
已知方程x2+y2+4x-2y-4=0,则x2+y2的最大值是( )
已知:C1:x2+y2+4x+4y-1=0 (x2和y2是 x和y的平方)C2:x2+y2+2x+2y-1=0相交于AB