x∧3+3x∧2-4 分解因式，x³+3x²-4=(x³-1)+(3x²-3)=(x-1)(x²+x+1)+3(x+1)(x-1)=(x-1)(x²+x+1+3x+3)=(x-1)(x²+4x+4)=(x-1)(x+2)²
