(x+1)(x+3)-(x-2)²=x²+4x+3-(x²-4x+4)=x²+4x+3-x²+4x-4=8x-1
(x+1)(x+3)-(x-2)平方=x^2+4x+3-x^2+4x-4=8x-1
x^4+6*x^3+19*x^2+30*x+25
8x-1
