x²-(x+2)(x-2)-(x+3)².求大师们速速回答!要有正确的解题方法!

x²-(x+2)(x-2)-(x+3)².求大师们速速回答!要有正确的解题方法!
x²-(x+2)(x-2)-(x+3)².求大师们速速回答!要有正确的解题方法!

x²-(x+2)(x-2)-(x+3)².求大师们速速回答!要有正确的解题方法!
x²-(x+2)(x-2)-(x+3)²
=x²-（x²-4）-（x²+6x+9)
=x²-x²+4-x²-6x-9
=-x²-6x-5