因式分解:9x2-y2-4y-4=______.
因式分解:9x2-y2-4y-4=______.
因式分解:1-x2+4xy-4y2=______.
已知x2+4x+y2-2y+5=0,则x2+y2=______.
将下列式子因式分解:x-x2-y+y2=______.
因式分解:(x2+2x+1)-y2=______.
因式分解:-3x2+6xy-3y2=______.
分解因式:9-6y-x2+y2=______.
2x2+xy-3y2+x+4y-1因式分解
已知x-y=2,则x2-y2-4y=______.
已知x2-4y2=20,x+2y=5,则x=______,y=______.
若x2-4x+y2+6y+13=0,则x=______,y=______.
已知x+y=4,xy=2,则x2+y2+3xy=______.