初一 数学 解方程 请详细解答,谢谢! (15 22:10:32)

2(X+4)^2-(X+5)^2-(X+3)(X-3).
=(x+4)^2-(X+5)^2+(x+4)^2-x^2+9
=(x+4+x+5)(x+4-x-5)+(x+4-x)(x+4+x)+9
=-(2x+9)+4(2x+4)+9
=-2x-9+8x+16+9
=6x+16
=-2*6+16
=4

题目错了吧
2(x+4)^2-(x+5)^2-(x+3)(x-3)
=(x+4)^2-(x+5)^2+(x+4)^2-(x^2-9)
=(x+4+x+5)(x+4-x-5)+(x+4)^2-x^2+9
=(2x+9)(-1)+(x+4-x)(x+4+x)+9
=-2x-9+4(2x+4)+9
=-2x+4(2x+4)
=6x+16
把X=-2 带入上式
6×(-2)+16
=4

^2是平方

2*(x^2+8x+16)-(x^2+10x+25)-x^2+9=6x+16=4