(x+1)(x²+x+1)-(x-1)(x²-x+1)=(4x+3)(x-2)2x(x+1)-(3x-2)x+21²=x²+1
(x+1)(x²+x+1)-(x-1)(x²-x+1)=(4x+3)(x-2)
2x(x+1)-(3x-2)x+21²=x²+1
x(x-3)小于3x(x+2)-2x²-3