5x-3x=9 详细解法。5x-3x=9 解：2x=9 2x÷2=9÷2 x=4.5x³＋5x²＋3x－9分解因式x^3+5x^2+3x-9 =(x^3-1)+(5x^2+3x-8) =(x-1)(x^2+x+1)+(5x+8)(x-1) =(x-1)(x^2+x+1+5x+8) =(x-1)(x^···