解(x²+4y²)²-16x²y²=(x²+4y²)²-(4xy)²=[(x²+4y²-4xy][(x²+4y²+4xy]=(x-2y)²(x+2y)²
原式=(x²+4y²)-(4xy)²=[(x²+4y²)+4xy][(x²+4y²)-4xy]=(x+2y)²(x-2y)²=[(x+2y)(x-2y)]²原式=(x²+y²)²-x²y²=(x²+y²)²-(xy)²=(x²+y²+xy)(x²+y²-xy)
平方差公式,A²-B²=(A+B)(A-B)