苏引华演讲视频下载:25253Afixed%25253B%25250D%25250Abackground-repeat%25253Arepeat-x%

25253Afixed%25253B%25250D%25250Abackground-repeat%25253Arepeat-x% B*B=2B里*是什么意思? a*a-b*b-2b-1 a*a+3b*b≥2b(a+b) a^2+b^2=(a+b)(a-b)吗？ (a+b)(a-b)+a(2b-c)因式分解 B-2牛B还是F-117牛B？ 化简：b/(a+b) + b/(a -b) +(a^2+b^2)/(a^2 -b^2) 化简：(a+b)^2(b+c-a)(c+a - b)+(a - b)^2(a+b+c)(a+b - c) (-2b-5)(-2b+5)