原式=(3x^4+3x³)-(7x³+7x²)-(7x²+4x-3)=3x³(x+1)-7x²(x+1)-(7x-3)(x+1)=(x+1)(3x³-7x²-7x+3)=(x+1)[(3x³+3x²)-(10x²+7x-3)]=(x+1)[3x²(x+1)-(10x-3)(x...