因为
x²+2x=2
x(x²+2x)+2x²+2x-6
=2x+2x²+2x-6
=2x²+4x-6
=2(x²+2x)-6
=2x2-6
=4-6
=-2
x4+2x^3-x²-2x-2
=x²(x²+2x)-(x²+2x)-2
=2x²-2-2
=2x²-4
第二问是否漏掉x?
因为
x²+2x=2
x(x²+2x)+2x²+2x-6
=2x+2x²+2x-6
=2x²+4x-6
=2(x²+2x)-6
=2x2-6
=4-6
=-2
x4+2x^3-x²-2x-2
=x²(x²+2x)-(x²+2x)-2
=2x²-2-2
=2x²-4
第二问是否漏掉x?