第一题 =3x²-2x²-5x+1-3x-1
=x²-8x
=(10)²-8*10
=100-80
=20
第二题 =x(2x-4x²+1-2x)-4x(x-x²-1+x)
=2x²-4x^3+x-2x²-4x²+4x^3+4x-4x²
=5x-8x²
=8*(-1/2)^2+5*(-1/2)
=2-5/2
=-1/2
第一题 =3x²-2x²-5x+1-3x-1
=x²-8x
=(10)²-8*10
=100-80
=20
第二题 =x(2x-4x²+1-2x)-4x(x-x²-1+x)
=2x²-4x^3+x-2x²-4x²+4x^3+4x-4x²
=5x-8x²
=8*(-1/2)^2+5*(-1/2)
=2-5/2
=-1/2