x²-4y²-3x-2y+k
=x²-3x+(3/2)²-4[y²+y/2+(1/4)²]-9/4+1/4+k
=(x-3/2)²-4(y+1/2)²+k-2
当k-2=0,即k=2时,上式可用平方差公式分为两个一次因式之积
x²-4y²-3x-2y+2
=(x²-3x+9/4)-(4y²+2y+1/4)
=(x-3/2)²-(2y+1/2)²
=(x-3/2-2y-1/2)(x-3/2+2y+1/2)
=(x-2y-2)(x+2y-1)
x²-4y²-3x-2y+k
=x²-3x+(3/2)²-4[y²+y/2+(1/4)²]-9/4+1/4+k
=(x-3/2)²-4(y+1/2)²+k-2
当k-2=0,即k=2时,上式可用平方差公式分为两个一次因式之积
x²-4y²-3x-2y+2
=(x²-3x+9/4)-(4y²+2y+1/4)
=(x-3/2)²-(2y+1/2)²
=(x-3/2-2y-1/2)(x-3/2+2y+1/2)
=(x-2y-2)(x+2y-1)