计算(x-5)(x+5)-(x+1)(x+5)要有步骤

原式=（x+5）[(x-5)-(x+1)]
=(x+5)(x-5-x-1)
=-6(x+5)
=-6x-30

=(x+5)(x-5-x-1)
=(x+5)*(-6)
=-6x-30

不是吧
现在的人怎么都这样呢 ？
(x+5)*[(x-5)-(x-1)]
=(x+5)*(-4)
=-4x-20

(x-5)(x+5)-(x+1)(x+5)
=(x-5)x＋(x-5)×5－（x+1)x＋(x+1)×5
=(x×x－5x)＋（5x－25）－(x×x＋x)＋(5x＋5)
=x×x－5x＋5x－25－x×x－x＋5x＋5
=4x－20