(x-3)(x-3)-6(x的2次方+x-1)
=x²-9-6x²-x+1
=-5x²-x-8
（2x+1)的2次方-（x+3）的2次方-（x-1）的2次方+1
=4x²+4x+1-x²-6x-9-x²+2x-1+1
=2x²-8