[(x-y)^7]÷（y-x)³-[4(x-y)²]²

[(x-y)^7]÷（y-x)³-[4(x-y)²]²
[(x-y)^7]÷（y-x)³-[4(x-y)²]²

[(x-y)^7]÷（y-x)³-[4(x-y)²]²
[(x-y)^7]÷（y-x)³-[4(x-y)²]²
=[(x-y)^7]÷[-（x-y)³-16(x-y)^4
=-(x-y)^4-16(x-y)^4
=-17(x-y)^4

原式=(x-y)^7÷[-(x-y)^3]-16(x-y)^^4
=-(x-y)^4-16(x-y)^4
=-15(x-y)^4

（y-x)³=-（x-y)³
则
[(x-y)^7]÷（y-x)³=-(x-y)^4
而[4(x-y)²]²=16(x-y)^4
则[(x-y)^7]÷（y-x)³-[4(x-y)²]²=-(x-y)^4-16(x-y)^4=-17(x-y)^4