(x2+y2-a2)2-4x2y2=（x²+y²-a²+2xy）(x²+y²-a²-2xy)=[(x+y)²-a²][(x-y)²-a²];=(x+y+a)(x+y-a)(x-y+a)(x-y-a)很高兴为您解答,skyhunter002为您答疑解惑如果本题有...